M4maths Previous Puzzles

05 Sep 2017 Time and Work

P can do a work in 14 days. Q can do the same work in 7 days and R can do the same in 10.5 days. Q and R start the work and leave after 3 days. P finishes the remaining work in X days. What is the value of X^2?

OPtion

1) 2.5 days
2) 1.5 days
3) 1.75 days
4) 2.0 days
5) 4.0 days
6) 4.5 days
7) 5 days
8) 5.5 days
9) 16.0 days
10) None of these

Solution

Amount of work done by Q and R in 3 days = 3*(1/7 + 2/21) = 15/21 = 5/7

Amount of work remaining after 3 days = 2/7

Amount of work done by P in 1 day = 1/14
So for 1/14 work P takes 1 day
Hence for 2/7 work P would take (1/(1/14))*2/7 = 4 days
So X=4 and X^2 =16

Correct Option: 9 Best Solution (25)

AYAN PAUL   7 years AGO

Q can do a piece of work in (1/7) days and R can do a piece of work in (1/10.5) days
So both Q & R do (1/7+1/10.5) = 25/105 work in 1 day
in 3 days they will perform 25/105*3 = 25/35 work
Remaining work = 1-(25/35) = 10/35
This can be performed by P in 10/35*14 = 4 days which is the value of x
So square of x will be 16

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kasarla swathi   7 years AGO

Q and R work in 3days=3(1/7+1/10.5)=5/7
the remaining 2/7 work is done by P and it does 1/14 work in 1day hence (2/7)/(1/14)=4
therefore P requires 4days and 4^2=16

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palak Jain   7 years AGO

let total work be 45
p 1 day work 3
q 1 day work 6
r 1 day work
3 day work by q and r is 30
work left is 12
p take 4 days
4^2=16

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Sasirekha   7 years AGO

P can complete 3 parts of work in a day.
Q can complete 6 parts a day.
R can complete 4 parts a day.
So Q+ R can complete 30 parts of work in 3 days.
P has to complete 12 parts of work.
So P can complete 12 parts of work in 4 days.
Question raised was X^2 so 16.0.😃

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shreya   7 years AGO

Q+R complete work in 4.2 days... therefore in 3 days complete 0.7142th work therefore remaining 0.2857 work to be completed by P
P complete work in 14 day... so 0.2857th work in 4 days...square of 4 =16days

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Priyanka devi E   7 years AGO

Q and R togerther completes 5/7(3*((1/7)+(1/10.5))) part of work in 3 days.
So, the remaining part of work is 2/7..
P completes 1/14 work in 1 day.
hence P takes 4 days to complete remaining work.
So X=4
and X^2 is 16.0

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Manisha   7 years AGO

Q and R 3 days work = 75/105
remaining work= 30/105
P will do it in 4 days
hence 16 is ans

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Dhanya   7 years AGO

P can do a work in 14 days
Q in 7 days
R in 10.5 days
L.C.M = 147
then P per day 10.5 units of work
Q per day 21units of work
R per day 14 units of work
three days Q and R can complete 105units of work remaining 42 units will be completed in 4 days by P they asked 4^2=16

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manvi   7 years AGO

1/7+1/10.5 =25/105
25/105*3 =5/7
remaining work = 1-5/7 =2/7
p alone can finish the work = 2/7*14 =4 days
square of 4 = 16 days

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yamini velaga   7 years AGO

let the total work to be done is 'y'
P can complete (y ÷ 7) work in 1 day
Q can complete (y ÷ 10.5 ) work in 1 day
R can complete ( y÷ 14 ) work in 1 day
then (3y ÷ 7) + ( 3y ÷ 10.5 ) + (X ×y ÷ 14) = y
---> X = 4
----> X^2 = 16 days

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Bodla Anupriya   7 years AGO

work done by Q and R in 3 days is 3(1/7 +1/10.5)=5/7
the remaining work is 2/7th part
2/7th part of work done by p is 4days(x value)
x^2=4^2=16
option 9

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C.Praveena   7 years AGO

(q+r)'s 1days work=[0.238]
work done by q and r in1day =0.741
remaining work =0.285
now 1/14 work is done by p in one day
work done by p in 14 days =14*0.285=4
therefore 4*4=16 days

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Nalli sowmya   7 years AGO

P q r work (lcm p,q,r
14 7 10.5 420units
30u 60u 40u
Q and r did work for 3days both can do 100u per day so for 3 days 300u work remaining 420-300 =120 u
Now only p should complete we know that time=work/efficiency =>120/30=>4 where In ques 4^2=16

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neha   7 years AGO

1 day work of Q and R= 1/7 +1/10.5
=(15+10)/105 =25/105
3 days work of Q and R=75/105
Remaining work=30
1 day work of P= 1/14 = 7.5/105
to complete work 30 P has work for 4 days
i.e. X=4
X^2=16

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Shuvadip Ghosh   7 years AGO

p and q's 3days work = 1/7 + 1/10.5 = 5/7
remaining 1- 5/7 = 2/7
1/14 is done by p in 1day
so,2/7 in 16 days

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sandhiya.n   7 years AGO

[q+r]'s one day work =[1/7+1/10.5]=0.238
q and r work in 3 days =0.714
remaining work=0.285
now 0.285 ,work done by p=[0.285*14]=4
therefore remaining work done by p=4*4=16

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priyadharshini.k   7 years AGO

work done in one day=(1+7)/(1+10.5)=0.238
work done by (q and r) in three days=0.714
remaining work=1-0.714=0.285
work done by p in 14 days=0.285*14=4
the value of (4*4)=16

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Attar Tajoddin Jamir   7 years AGO

After 3 days Q and R will complete (5/7)th of work and remaining 2/7th of work completed in 4 days and 4^2=16

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Narasimha   7 years AGO

q+r=2.5/10.5
work in 3 days=5/7
remaining=2/7
it will done by p in 4 days
x^2=16

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Rajesh Arora   7 years AGO

3 day work of q and r is (1/7+1/10.5)=5/7
1-5/7 is remaining work.
remaining work Done by p Which is 2/7*14

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ANANDA PRIYA T.R   7 years AGO

Q+R=(1/7)+(1/10.5)
P=1-(Q+R) *3=. 285
0.285*14=4
4^2=16

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raksha s shetty   7 years AGO

Q in 3 days completes 300/7% of work
R in 3 days completes 300/10.5% of work
remaining work is 200/7%
p completes it in x=4 days
and x^2=16days

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Abhijith Sankar E U   7 years AGO

P's 1 day work = 1/14
Q's 1 day work = 1/7
R'S 1 day work = 1/10.5
work done all 3
1 = 3*(1/7+1/10.5)+x*1/14
x = 4
x^2 = 16

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atheesh padala   7 years AGO

Q and R 3 days work is 75/105
remaining work is 30/105 can be completed by P in 4 days
so the ans is 4^2=16

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Varun   7 years AGO

Work per day = 1/(No. Days required to complete work)
Given, 1- 3*(1/7+1/10.5) = 1/14 X
=> X = 4
Hence X ^ 2 = 16

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