C is 20 more efficient than A A &B can finish

C is 20% more efficient than A. A &B can finish the work in 16 days. B &C can finish the work in 15 days. In how many days A alone can do the same piece of work?

A. 42

B. 48

C. 54

D. 36

Answer: Option B

Solution(By Examveda Team)

A and B can finish the work in 16 days.
Work rate of,
(A + B) = 100/16 = 6.25% per day. ------------------- (1)
Work rate of,
B + C = 100/15 = 6.66% per day --------------------- (2)
Now,
C = A + 20% of A = 1.2 A ----------------------------------- (3)
Equations (1) - (2),
A + B - B - C = 6.25 - 6.66
A - C = - 0.41 ----------------------------------- (4)
Using equation (3),
A - 1.2 A = - 0.41
A = 2.05% per day.
So, A can complete the work in,
= 100/2.05 = 48 days (Approx.)

Fraction Method
Just Replace, 100% by 1.
A and B can finish the work in 16 days.
Work rate of,
(A + B) = 1/16 part per day. ------------------- (1)
Work rate of,
B + C = 1/15 part per day --------------------- (2)
Now,
C = A + 20% of A = 1.2 A ----------------------------------- (3)
Equations (1) - (2),
A + B - B - C = 1/16 - 1/15
A - C = -(1/240) ----------------------------------- (4)
Using equation (3),
A - 1.2 A = - (1/240)
.2A = 1/240
A = 1/(240*0.2) = 1/48 part per day
So, A can complete the work in,
= 48 days.

Comments ( 2 )

The Firminator :

4 years ago

@Parasaran c is 20% more efficient
20% is 1/5 is fraction 20/100
So A is 5 and c is 6 i.e (5+1)

Now A+B= 16
And B+C= 15

If two take lcm of 16 and 15 which is 240 and that is your total work

Now efficiency of A is 5

Time taken by A is 240/5 = 48
Parasaran N :

7 years ago

Please explain without percentages plz.....

C is 20% more efficient than A. A &B can finish the work in 16 days. B &C can finish the work in 15 days. In how many days A alone can do the same piece of work?

Solution(By Examveda Team)

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Comments ( 2 )

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