Question

Shanu and Pawan working alone can finish a piece of work in 10 days and 15 days respectively. If shanu and pawan work together, but shanu leaves the job after 2 days. How much of the work is left then? ​

Answer 1

Answer:

10 days

Step-by-step explanation:

work done by Shanu in 1 day= 1/10

work done by pawan in 1 day= 1/15

now work done by both in one day = 1/10+1/15= 5/30 = 1/6

work done by both in 2 days = 1/6×2=1/3

now remain work = 1-1/3 = 2/3

now again time taken by pawan to do the work in one day 1/15

time taken by pawan to complete work= 1_15

time taken by pawan to complete remain work=

2/3_15×2/3= 10 days

Answer 2

Answer:

If Shanu and Pawan when working separately can finish work in 10 and 15 days respectively, then if they work together and Shanu leaves after 2 days, 2/3 rd of the total amount of work is left

Step-by-step explanation:

Let W be the total amount of work

Given Shanu requires 10 days for completing W work

Work he can do 1 day = W/10

Also,

Pawan requires 15 days to complete W work

So work he can do in 1 day = W/15

If they work together, then the amount of work done in 1 day = W/10 + W/15

$= \frac{10W+15W}{10*15}\\\\= \frac{25W}{150} \\\\=\frac{W}{6}$

So 1/6 th of total work is completed in 1 day

So, the amount of work done in 2 days = 2*W/6 = W/3

So, 1/3 rd of total work is done in 2 days

Remaining work is

$W-\frac{W}{3} \\\\= \frac{3W-W}{3} \\\\= \frac{2W}{3}$

So, 2/3 rd of total work is left to do