Supriya Mondal   9 years AGO

Ratio of gold and copper in C will be=(7/9+7/18):(2/9+11/18)
=(21/18):(15/18)
=7:5
So, option 4)7:5 is the right answer

Like? Yes (41) | No (9)  

Ayan Patra   9 years AGO

In alloy A per (7+2) 9 unit, gold is 7 and copper is 2.
In alloy B per (7+11) 18 unit, gold is 7 and copper is 11.
So to mix A and B in equal quantity we need 2 x A for each B.
So 2 x A means - gold:copper = 14:4
Now alloy C = A + B = 14:4 + 7:11 = 21:15 = 7:5.
Therefore new alloy has gold:copper at 7:5 ratio.

Like? Yes (38) | No (7)  

Dinni   9 years AGO

Ratios and proportions
Gold in c =7/9+7/18=21/18.
Copper in c =2/9+11/18=15/18.
Gold & cu ratio =(21/18)/(15/18) = 21/15 = 7/5.

Like? Yes (19) | No (1)  

RAKESH   9 years AGO

(7/9 + 7/18 ) : (2/9 +11/18)

= 21:15 = 7:5

Like? Yes (24) | No (7)  

Pranati Kundu   9 years AGO

IN A Alloy-multiply 7:2 by 2, u get 14:4 now total parts are 18 in A alloy and total parts in B alloy are also 18 that is 7:11.now u can add directly gold with gold and copper with copper bcz total parts are equal.7+14:4+11.u get 21:15 which is equal to 7:5

Like? Yes (9) | No   

Karthick Raja   9 years AGO

in alloy A the ratio of gold and copper is 7:2
in alloy B the ratio of gold and copper is 7:11

in c alloy equal quantities of alloy A and Alloy B mixed
so we didn't considered quality

amount of gold in alloy A 7/9
Amount of gold in alloy B 7/18

total amount of gold in alloy c = (7/9)+(7/18)=21/18. for 1 quantity of Alloy A and Alloy B

total amount of copper in alloy A = (2/9)
total amount of copper in alloy B = (11/18)
total amount of copper in alloy C =(2/9)+(11/18)=(15/18) for one quantity mixture of alloy A and alloy B.

In Alloy C the ratio of Gold and Copper is (21/18):(15/18)

21*18:15*18
21:15
7:5
so the ratio of gold and copper ratio in alloy C is 7:5

Like? Yes (8) | No   

sompon temtheerakij   9 years AGO

equal quantities , so
A ; gold : copper = 14 : 4
B : gold : copper = 7 : 11
C : gold : copper = 21 : 15 = 7 : 5

Like? Yes (4) | No   

SAYAN CHATTERJEE   9 years AGO

in the new alloy -- gold:coppper
=(7x/9+7x/18):(2x/9+11x/18)
= 7:5 (4).

Like? Yes (4) | No   

anubhav verma   9 years AGO

for b in 18 we have 7g and 11c. therefore for 9 we get 3.5g and 5.5g . now quantity of a and b are same hence 7+3.5=10.5g and 2+5.5=7.5c...
ratio105:75=7:5

Like? Yes (3) | No   

ravi singh   9 years AGO

answer is 7:5

since quantity is same hence,
in alloy A gold is 14 and copper is 4
and in alloy B gold is 7 and copper is 11
hence in alloy C gold is 21 and copper is 15
hence ratio is 21:15=7:5

Like? Yes (4) | No (1)  

shivaprabhu   9 years AGO

gold in alloy Ag =7/9 and copper is Ac=2/9

similarly gold in alloy B is Bg=7/18 and copper Bc=11/18
since equal quantities are melted to for alloy c
therefore gold in alloy C is Cg=(Ag+Bg)/2
i.e Cg=(7/9 +7/18)/2
= 7/12
similarly
Cc=(2/9 +11/18)/2
=5/12

Therefore ratio of C is C=Cg/Cc
=(7/12)/(5/12)

Ans C=7:5

Like? Yes (3) | No   

Math Lovers   9 years AGO

for metal A-
gold = 7x kg
copper = 2x kg

for metal B
gold = 7y kg
copper = 11y kg

now for same quatities -

7x + 2x = 7y+11y
=> x = 2y

so in metal C

ratio = total gold/total copper = (7x+7y)/(2x+11y)
put x=2y and solve

so ratio = 21/15 = 7/5

Like? Yes (3) | No   

Maria   9 years AGO

Total gold=7x/(7+2)+7x/(7+11)=21x/18
Total copper=2x-21x/18=15x/18
so ratio of gold and copper to make alloy c is 21x:15x=7:5

Like? Yes (2) | No   

Venkatesh kadali   9 years AGO

g : c
a: 7:2 *2 -->a: 14:4
b: 7:11 -->b: 7:11 differences are equal
c: a+b:a+b=14+7:4+11
=21:15
c=7:5

Like? Yes (4) | No (2)  

viswambher   9 years AGO

in alloy A let there be 7kgs of gold and 2kgs of copper and in alloy B let there be 7kgs gold and 11kgs copper
so if 18 kgs of alloy A and 18 kgs of alloy B are mixed to form alloy C then in the alloy C there is 21 kgs of gold and 15kgs copper therefore it is in the ratio 7:5

Like? Yes (4) | No (2)  

prabhat kumar   9 years AGO

g=7/9+7/18=21/18
c=2/9+11/18=15/18
so new ratio will be 7/5

Like? Yes (2) | No   

P.ARUNA   9 years AGO

alloy 1=7:2
alloy 2=7:11
alloy 3=>gold=(7/9+7/18) : copper=(2/9+11/18)
=21:15
=7:5

Like? Yes (2) | No   

padam   9 years AGO

gold in alloy A=7/9 and copper is 2/9
gold in alloy B=7/18 and silver is 11/18
now in alloy c gold is 21/18 and silver is 15/18
ratio is 7:5

Like? Yes (4) | No (2)  

RAVAL   9 years AGO

here,
* B=2A
* 2A+B=C
so,C= 21:15= 7:5

Like? Yes (2) | No   

Ramdas Singathiya   9 years AGO

let assume first alloy=9kg and second alloy =18 kg
now mix 9 kg of each so in new alloy gold=10.5 kg and copper=7.5 kg so ratio=7:5

Like? Yes (1) | No   

vini   9 years AGO

Make the ratio to equal parts because equal quantities are taken to C
In A 7:2
In B 7:11
B has 18 parts, making A to 18 parts so the ratio becomes 14:4( proportion wont change)
Mixing A and B into C
so the ratio of gold and copper in C is
21:15
ie., 7:5

Like? Yes (1) | No   

mohita verma   9 years AGO

the reason is very simple...
gold is {(7/(7+2))+(7/(7+11))}=21/18
silver is {(2/(7+2))+(11/(7+11))}=15/18
gold to silver ration is=21/15 i.e. 7:5

Like? Yes (1) | No   

Rohit Gurjar   9 years AGO

7/9+7/18= 2/9+11/18
21:18 =15:18
21:15
7:5

Like? Yes (1) | No   

Mani Sachdev   9 years AGO

gold in C=(7/9+7/18)=7/6
Copper in C=(2/9+11/18)=5/6
gold:Copper=7/6:5/6=7/5
7/5 Ans

Like? Yes (1) | No   

neha gupta   9 years AGO

Let 1kg of both alloys are taken
then in alloy A:
gold content=7/9
copper content=2/9
and in alloy B :
gold content=7/18
copper content=11/18
If they are mixed together then :gold content=7/9 + 7/18 = 21/18
copper content=2/9+ 11/18 = 15/18
Dividing both we get 21:15 = 7:5

Like? Yes (1) | No   

W J Krishna Teja   9 years AGO

In A gold and copper is in the ratio 7:2
let the copper and gold be in the amounts 14g and 4 g respectively.
In B copper and gold are in the ratio 7:11
let the amount of copper and gold be 7g and 11g respectively.
so, Now wt of A is 18 g(14g copper+4g gold)
and B is 18 g(7g copper+11g gold)
these equal amounts of A and B are mixed and melted to form C which contains (14+7)g copper and (4+11)g gold
therefore ratio of copper and gold in C is (14+7):(4+11)
= 21:15
= 7:5

Like? Yes (2) | No (1)  

B.venkata suresh   9 years AGO

gold in 2 kg C = 7/9 + 7/18

= 7/6 kg

And Quantity of copper in 2 kg C = 2 – 7/6

= 5/6 kg

∴ Required ratio = 7/6 : 5/6 = 7 : 5

Like? Yes (1) | No   

swetha   9 years AGO

Quantity of gold in A = 7/9* wt. of A

Quantity of gold in B = 7/18* wt. of B

If 1 kg of each A and B are mixed to form third alloys C.

Then quantity of gold in 2 kg C = 7/9 + 7/18

= 7/6 kg

And Quantity of copper in 2 kg C = 2 – 7/6

= 5/6 kg

∴ Required ratio = 7/6 : 5/6 = 7 : 5

Like? Yes (1) | No   

ammar   9 years AGO

First of all convert ratios to equal no. of parts.
Composition of alloy A = 2(7:2) = 14:4
Composition of alloy B = 7:11
After mixing,
No. of parts of gold in mixture = 14 + 7 = 21
No. of parts of copper in mixture = 4 + 11 = 15
Therefore, gold:copper = 21:15 = 7:5

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NESAB JAFAR   9 years AGO

7/9+7/18=21/18
2/9+11/18=15/18
mixture=21:18
7:5

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ROHIT JAIN   9 years AGO

we will add 7:2 which will become (7+2) 9 &
(7:11) 18.
LCM of 9 and 18 are 18.

so we will convert ratio into accordingly
now ratio became 7:2 to 14:4
& 7:11 will remain same.

now add respectively
New ratio = 21 : 15
= 7 : 5

Like? Yes (1) | No   

sai   9 years AGO

a gold=7/9 copper 7/18
b gold=7/18 copper 11/18
1:1 ratio
ixture 7:5

Like? Yes (1) | No   

saibabu   9 years AGO

gold in (7/9)+(7/18) units = 7/6 units
copper in (2/9)+(11/18) units = 5/6 units
c=gold=(7/6) : (5/6) = 7 : 5.

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HARMEET KAUR   9 years AGO

A and B are two alloys of gold and copper prepared by mixing metals in the ratio 7:2 and 7:11 respectively. If equal quantities (18 gms) of alloys are melted to form a third alloy C, then quantity of Gold and copper in C are (14+7=21gms) & (4+11=15 gms) respectively and hence ratio of gold to copper is 21:15 or 7:5.

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ADERU CHENCHU NITHISH   9 years AGO

gold=(7/9)+(7/18)=7/6
copper=(2/9)+(11/18)=5/6
so C alloy ratio=7:5

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Yashi Das   9 years AGO

Let 1kg of A and B be taken to form 2kg of C
Therefore,Gold in 1kg of A=7/9 ,copper in 1kg of A=2/9
Gold in 1 kg of B=7/18,copper in 1kg of B=11/18
Gold in 2 kg of C=(7/9+7/18)=7/6
Copper in 2 kg of C=(2/9+11/18)=5/6
Ratio of Gold to copper in C=(7/6):(5/6)=7:5

Like? Yes (1) | No   

veeramanikandan   9 years AGO

C={7/9+7/18} =7/6.
C={2/9+11/18}= 5/6
G:copper= 7/6:5/6=7:5

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udaya   9 years AGO

Gold ratio=7/9+7/18=21/18
copper ratio=2/9+11/18=15/18

gold ratio:copper ratio
21/18:15/18=7:5

Like? Yes (1) | No   

Thilaka Elangovan   9 years AGO

gold ratio=7/9+7/18 =7/6
copper ratio=2/9+11/18 =5/6
c's ratio = 7:5

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pratap kumar sahoo   9 years AGO

A:gold=7/9
copper=2/9

B:gold=7/18
copper=11/18

when A and B are mixed equally then,
gold=(7/9)+(7/18)=21/18
copper=(2/9)+(11/18)=15/18

so, G: C=7:5

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Rahul Raj Barnwal   9 years AGO

in alloy c for equal quantity of alloy 1 and alloy 2 there is
(7*2 + 7)/(2*2 + 11) = 21/15 = 7/5

Like? Yes (1) | No   

upama ghosh   9 years AGO

equal quantity lets say x kg of both the metals are mixd.so total quantity of gold is 7x/6 and copper is 5x/6.so ratio of two metals is 7:5

Like? Yes (1) | No   

RAKESH ARYA   9 years AGO

G:C= (7/9*1/2 + 7/18*1/2) / (2/9 * 1/2 + 11/18 *1/2 )
= 21/ 15
=7 /5
=7 :5

Like? Yes (1) | No   

manju   9 years AGO

9kg of A contains 7G, 2C
18Kg of B contains 7G, 11C
Take 18kg of A and 18kg of B
We get 21G, 15C
7: 5

Like? Yes (1) | No (1)  

Surit Datta   9 years AGO

After solving we get that the ratio of Gold and Copper is 7 : 5
so option 4
that's it.

Like? Yes (1) | No (1)  

vishal chandrola   9 years AGO

gold in alloy c=(7/9+7/18)=21/18=7/6 units
copper in alloy=(2/9+11/18)=15/18=5/6 units
ratio of gold:copper is

7/6:5/6= 7:5

Like? Yes (1) | No (1)