Question

A is twice as fast as B and B can finish a work in 30 days. If A and B work together the number of days required to complete the same work is:

Answer 1

Answer:

Here, A is twice faster than B. It means if B does a work in 2 days, A will do the same work in half of B or 1/2 x 2 days or in 1 day.

By question,

B can do a work in 30 days

So, A will do this work in just half of B or 30/2 days

= 15 days

Now, if both A and B will work together the they will finish the work in

1 / 30 + 1 / 15 days = 1 +2 /30

= 3/30 days = 1/10 = 10 days.

Answer 2

Step-by-step explanation:

Amount of work B can do in 1 day = 1/30

Amount of work A can do in 1 day = 2 × 1/30 = 1/15

Amount of work both can do in 1 day = 1/30 + 1/15 = 1/30 + 2/30 = 3/30 = 1/10

So, both will complete the work in 10 days if they worked together.