Question

P and Q together can complete a work in 20 days. If P alone can complete the same work in 36 days, then in how many days Q alone can complete the same work?

• A. 48 days
• B. 42 days
• C. 45 days
• D. 51 days

Answer 1

Answer:

C. 45 days

Solution:

GIVEN:

P and Q together can complete a work in 20 days

P alone can complete same work in 36 days.

CONCEPT:

We will use L.C.M. approach

CALCULATION:

Let work be L.C.M. of 20 and 36 i.e. 180 units

P and Q together work in one day = 180/20 = 9 units

P work in one day = 180/36 = 5 units

→ Q work in one day = (9 – 5) = 4 units

→ So, time taken by Q to complete work = 180/4 = 45 days.