Question

A can do a work in 24 days. B is 20% more efficient than A. If C can do the work in 10 more days than B, find the time taken by A and C together to complete the work.
A. 43/3 days
B. 40/3 days
C. 50/3 days
D. 41/2 days
E. None of these

Answer 1

A will do 1/24 part of the work in 1 day.

B → (1/24)×(120/100)=1/20

C→ 1/30

A+C→ (1/24)+(1/30)= 3/40 part of work in 1 day

Taking the reciprocal, A and C will together completes the work in 40/3 days.

Answer 2

Answer:

(B) 40/3 days

Step-by-step explanation:

A can do the work in 24 days

⇒ 1 day = 1/24 of the work

B is 20% more efficient than A

⇒ Number of days needed =  24/(100 + 20) x 100 = 20 days

⇒ 1 day = 1/20 of the work

C can do the work in 10 more days than B

⇒ Number of days needed = 20 + 10 = 30

⇒ 1 day = 1/30 of the work

Together, A and C :

1 day = 1/24 + 1/30 = 3/40

Numbers of days needed = 40/3

Answer: (B) 40/3