Question

2. A can do a certain job in 25 days which B alone can do in 20 days. A started the work and was joined by B after 10 days. In how many days was the whole work completed?​

Answer 1

Answer:

Hence, total days = 7 + 8 = 15 days.

Step-by-step explanation:

A alone can complete a work in 25 days.

B alone can complete a work in 20 days.

Formula:

Total work = Efficiency × Time

Calculation:

Total work = 100 units [LCM of 25 and 20]

Efficiency of A = 4 units/day

Efficiency of B = 5 units/day

Work done by A in 7 days = 4 × 7 = 28 units

Remaining work = 100 – 28 = 72 units

∴ Time taken by A and B to complete remaining work = 72/(4 + 5) = 72/9 = 8 days

Hence, total days = 7 + 8 = 15 days.