Question

A and B take 6 hours and 9 hours respectively to complete a work. A works for 1 hour and then B works for two hours.
(i) How much work is done in these 3 hours ?
(ii) How much work is still left ?​

Answer 1

SOLUTION:-

Given

A Takes 6 hour to finish work

B takes 9 hours to finish same work

To find

(i) How much work is done in these 3 hours ?

(ii) How much work is still left ?

Explanation

A Takes 6 hour to finish work

B takes 9 hours to finish same work

A can do a piece of work in 6 hour , So

A can do a piece of work in 1 hour = 1/6 of work

And

B can do the same work in 9 hour , so

B can do a piece of work in 1 hour = 1/9 of work

Then

B can do a piece of work in 2 hour =1/9×2

= 2/9of work

1) Work is done in 3 hours =

$\frac{1}{6} + \frac{2}{9} \\ \\ = \frac{3 + 4}{18} \\ \\ = \frac{7}{18} of \: total \: work$

2) Work still left =

$1- \frac{7}{8} \\ \\ = \frac{18 - 7}{18} \\ \\ = \frac{11}{18} of \: work$

Hope IT helps u !!!