Question

A can complete $33\frac{1}{3}$ % of a work in 5 days and B can complete 40% of the same work in 10 days. They work together for 5 days and then B left the work. A alone will complete the remaining work in:

• A. $$7\frac{1}{2} days$$
• B. 5 days
• C. 7 days
• D. $$5\frac{1}{2}days$$

Answer 1

Answer:

C. 7 days

Solution:

Given:

A can complete the 33(1/3)% work in 5days

B can complete the 40% work in 10days

Calculation:

$33\frac{1}{3}$%$=\frac{1}{3}$

40%$=\frac{2}{5}$

Let the total work be 15 units

According to question:

A can complete the work 5 units of work in 5 days

B can complete the work 6 units of work in 10days

Efficiency of A = 5/5 = 1units/day

Efficiency of B = (6/10)units/day

When they work together:

Efficiency of the work = 1+ (6/10) = 16/10units/day

According to question they work for 5days

Work completed in 5days = (16/10) × 5 = 8units

Remaining work = 15 – 8 = 7units

A alone the remaining work in = total work / efficiency = 7 / 1 = 7days

∴  the required answer = 7days