90%(A) and 97%(B) pure acid solutions are mixed to obtain 21.0 litre of 95% pure acid solution, find

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27 Jun 2013 Problem

90%(A) and 97%(B) pure acid solutions are mixed to obtain 21.0 litre of 95% pure acid solution, find the amount of (B) to be mixed to form the mixture.

OPtion

1) 5 litre
2) 6 litre
3) 15 litre
4) 16 litre
5) 20 litre
6) 23 litre
7) 28 litre
8) 30 litre
9) 35 litre
10) None of these

Solution

Let 90% pure acid solution be A litre and 97% pure acid solution B
A+B = 21
90% of A + 97% of B = 95% of 21

=> 90A/100 + 97B/100 = 95*21/100
90A + 97B = 1995
By Solving A = 6, B=15
So 97% of pure acid is 15 Litre

Correct Option: 3 Best Solution (15)

krishnapriya   11 years AGO

let the amt of 90% pure solution be 'x' and 97% pure solution be 'y'(in litres)
so, total amt of solution=21
x+y=21--------(1)
total concentration of the solution =95%
90x/100+97y/100=95*21/100
90x+97y=1995------(2)
90x+97(21-x)=1995
so, x=6
hence y=15

Like? Yes (39) | No (3)  

Vinay Sipani    11 years AGO

(90x/100) + (97y/100) = (95*21/100)
=> 90x + 97y = 1995-----(1)

Also (x + y) = 21 ------(2)

=> x = 6 , y = 15

Like? Yes (12) | No (6)  

abhilasha uniyal   11 years AGO

90 (A) 97(B)
95
97-95=2 95-90=5
hence the ratio is 2:5
5/7*21 lts=15lts

Like? Yes (6) | No (2)  

Anil Kumar Bharti   11 years AGO

Ans: 3)15 litre
Exp:
Let A=x & b=21-x
90x+97(21-x)=21*95
solve it....
x=6
Then B=21-6=15

Like? Yes (4) | No (1)  

rajesh komal   11 years AGO

from the concept of mixture and allegations
we have A=90% and b=97% ,and mixture is 95%this can explained as
90% 97%
95%

(97-95) = 2 5= (95-90)

therefore the ratio of A &B in 95 % of mixture is ratio 2:5 in 21 liters of acid solution

now to calculate amount of B :

(5/7)*21=15

Like? Yes (4) | No (1)  

Roopam Jain   11 years AGO

by rule of alligation :
90 97
95
2 5

Ratio between A and B = 2/5
So amount of B = 21x5/7 = 15 litres

Like? Yes (7) | No (4)  

Deepak Sharma   11 years AGO

Let x litre of A and y litre of B Mixed.
Therefore
x+y=21
& 90x/100 +97y/100=21X95/100

After solving these equations

y= 15 so 15 litre of b to be mixed to form such type of a mixture.

Like? Yes (4) | No (1)  

Jasmine Khan   11 years AGO

x lit of A+ y lit of B=21 lit
0.90*x+0.97*y=21*0.95
0.90*(21-y)+0.97*y=19.95
18.9-0.90y+0.97y=19.95
0.07y=19.95-18.9=1.05
y=15

Like? Yes (6) | No (4)  

Ann Mary Jolly   11 years AGO

ANS : 15 litres
Let the amount of A and B required be x and y litres resp.Then total amount of acid
in the solution (in ml) = 900x+970y = 21*950 ....(1)
Total volume of the soln (in L) = x+y = 21 ....(2)
Solving (1) and (2),we get x = 6 and y = 15

Like? Yes (3) | No (1)  

N Sinha   11 years AGO

Ans: 3)15 Litre
Exp:
Let A=x & B=21-x
90x+97(21-x)=21*95
solve it....
x=6
So, B=21-6=15 LitreAns

Like? Yes (2) | No (1)  

anjul meid   11 years AGO

Let x and y be the amount of A and B type respectively. then 90x +97y=95*21;
and x+y=21 solving we get y=15

Like? Yes (3) | No (2)  

Dhivya   11 years AGO

the solution is
90%a+97%b=21%(95%)
so (90/100)a+(97/100)b=(95/100)21
so 90a+97b=95*21=1995
substituting abobe values we get
90(6)+97(15)=1995

so the value of b is 15

Like? Yes (4) | No (3)  

Angeline   11 years AGO

the solution is
90%a+97%b=21%(95%)
so (90/100)a+(97/100)b=(95/100)21
so 90a+97b=95*21=1995
substituting abobe values we get
90(6)+97(15)=1995

so the value of b is 15

Like? Yes (2) | No (1)  

anand s idagal   11 years AGO

Solve it by quadratic equation
X+y=21 (1)
90/100+97/100=95/100×21
I.e. 0.9x+0.97y=19.95 (2)
You will get x=6 n y=15
...so b is 15 litres

Like? Yes (2) | No (3)  

Md Intshamuddin   11 years AGO

let x% of A and y% of B be mixed then,x+y=21 and
(90/100)*x+(97/100)*y=(95/100)*21,on solving these equations we get,y=35,x=-14 litre

Like? Yes (2) | No (4)