Question

20. A can do 50% more work than as B can do in the same time.
B alone can do a piece of work in 20 hours. A, with help of B,
can finish the same work in how many hours ?
(b) 8 hours
(a) 12 hours
(C) 134 hours
)
(d) 5.
hours​

Answer 1

Answer:

(b) 8 Hours

Time required to complete the work for B = 20 hrs

∴ Work done by B in 1 hour = 1/20

Given A is 50% more efficient than B

∴ Work done by A in 1 hour = (3/2) × 1/20 = 3/40

∴ Work done by both A and B together in 1 hour = (3/40) + (1/20)

⇒ (3/40) + (1/20) = 5/40 = 1/8

⇒ Work done by both A and B in 1 hour = 1/8

∴ A and B can complete the work in 8 hours