equation of a line

Question

3 men or 8 boys can do a piece of work in 17days. Hw many days will 2 men and 6 boys together take to finish same work.?

Answer 1

One man will do 1 / (3 * 17) = 1 / 51 of the work in one day.

One boy will do 1 / (8 * 17) = 1 / 136 of the work in one day.

2 men and 6 boys will do:

(2 / 51) + (6 / 136) = 1/12 of the work in one day.

Hence, time taken to do all the work will be 1 / (1/12) = 12 days