Question

21. A and B can separately complete
a piece of work in 20 days and
30 days respectively. They
worked together for some time,
then B left the work. If A com-
pleted the rest of the work in 10
days, then B worked for
(1) 6 days (2) 8 days
(3) 12 days (4) 16 days


without x
please use trick​

Answer 1

Answer :

Option 1) 6 days

Explanation :

10 days work of A = 10 × 3

=> 10 days work of A = 30 units

Therefore, (60-30) = 30 units of work would have been done by A.

For B,

=> 30/(3+2)

=> 30/5

=> 6 days

Therefore, B worked for 6 days.

Answer 2

Solutions

according to question:-

A and B can separately complete

A and B can separately completea piece of work in 20 days

Work done by A in 10 days = 10/20 = ½

Days required by (A+B) together to complete ½ work =½ /(1/20 + 1/30)

= 6 days