Question

X and y can do a piece of work in 20 days and 12 days respectively. X started the work alone and then after 4 days .Y joined him till the completion of the work. How long did the work last? Select one: a. 10 days b. 6 days c. 20 days d. 15 days

Answer 1

$\huge\red{Answer}$

b. 6 days

$\huge\green{Explanation}$

Per day's work of x is 1/20

And per day's work of y is 1/12 days

So work done by x in first 4 days

= 1/20×4= 1/5

So the remaining work be

1-1/5=4/5

now work done by x and y together = 1/20 + 1/12

=2/15

So the remaining work be done by both x and y

= 2/15 ×D = 4/5

So D = 4/5×15/2 =3×2 = 6

Therefore for 6 days they worked till last

HOPE IT HELPS YOU ☺☺ !!