P can do a work in 20 days. Q can do the same work in 12 days and R can do the same in 16 days. Q an

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15 Jun 2018 Time and Work

P can do a work in 20 days. Q can do the same work in 12 days and R can do the same in 16 days. Q and R start the work and leave after 6 days. P finishes the remaining work in X days. What is the value of X?

OPtion

1) 5.0 days
2) 1.5 days
3) 1.75 days
4) 2.0 days
5) 2.25 days
6) 4.5 days
7) 2.5 days
8) 5.5 days
9) 6.0 days
10) None of these

Solution

Amount of work done by Q and R in 6 days = 6*(1/12 + 1/16) = 42/48 = 7/8
Amount of work remaining after 6 days = 1/8

Amount of work done by P in 1 day = 1/20
So for 1/20 work P takes 1 day
Hence for 1/8 work P would take (1/(1/20))*1/8 = 20/8 = 2.5 days

Correct Option: 7 Best Solution (10)

Devendra Marghade   5 years AGO

Total work = 6(1/12 + 1/16) + X/20 = 1
=> 7/8 + X/20 = 1
=> X/20 = 1/8
=> X = 2.5
Option 7)

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Varun   5 years AGO

Work done by P per day = 1/20
By Q = 1/12
By R = 1/16

Work by Q and R in 6 days = 6*(1/12+1/16) = 7/8

Remaining work by P = 1-7/8 = 1/8
And it is to be done by work at 1/20 rate = 1/8)/(1/20) = 2.5 days
= Option (7)

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Titir Misra   5 years AGO

P's 1 day work = 1/20
Q's 1 day work = 1/12
R's 1 day work = 1/16
Q+R 's 1 day work = 1/12+1/16 = 7/48
Q+R's 6 day work = 7/8
Work left= 1-7/8 = 1/8
Time taken by P = X= Work left/ P's 1 day work =(1/8)/(1/20)=5/2=2.5 days

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harshitha   5 years AGO

k is the work by Q the work is 6k/12 and by R the work done is 6k/16 the total work by O&R is 7k/8 remaining work is k/8=xk/20 done by p x=2.5

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Vishnuvarthini K   5 years AGO

total work lcm=240
efficiency of P=12 u/day
efficiency of Q=20 u/day
efficiency of R=15 u/day
efficiency of P and Q=35
6 days of P and Q= 35*6=210
remaining work of P= 30/12=2.5

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rajeev bommu   5 years AGO

Q and R for 1 day : 1/12 + 1/16 = 7/48
for 6 days: (7/48)*6 = 7/8
now only 1/8 work left to do
P can do the rest in 20/8 i.e, 2.5

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Dhiviyarasi E   5 years AGO

total work LCM=240
effc of P=12 u/days
effc of Q=20 u/days
effc of R=15 u/days
effc of P and Q=35
6 days of P and Q= 6*35=210
lcm-effc of r and q=240-210=30
remaining of P=30/12=2.5 days

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Sangeetha S   5 years AGO

Lcm=240 total work
eff of P=12 u/day
eff of Q=20 u/day
eff of R= 15 u/day
eff of p and q=35
6 days of r and q=35*6=210
240-210=30
remaining of p=30/12=2.5 days

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Narmadha   5 years AGO

work of P=12
work of Q=20
work of R=15
total work=240
efficiency of Q and R=(35*6)=210
total work-efficiency of Q and R=240-210=30/12=2.5

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kanishk vashistha   5 years AGO

Q can do a work in 12 days which means that in one day he can do 1/12 of work and same as with R he can do a work in 16 days that means in one day he can do 1/16 of work .Together they have worked for 6 days that means (1/12 + 1/16)6 viz...7/8.the remaining work is 1/8 which has been done by P and P can do a work in 20 days that means in one day he can 1/20 of work . let the days taken by P to do 1/8 be x. and in one day he can do 1/20,so 1/8 of work he can do in 2.5 days. (20/8)

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