Question

A room has to be painted and worker A does 1/3 of the work then leaves. Next worker B does 1/4 of the remaining work and then leaves and finally worker C does 1/5 of the remaining work and then leaves.

What fraction of the room still needs to be painted?
a)3/5
b)2/5
c)13/60
d)7/15

Answer 1

The Answer is C 13/60

Answer 2

S O L U T I O N :

Here, we are given that a room is painted by A, B and C so here three of them have done the work. So, we'll add all these fractions and assume the total work as 1 after that we will substract all the added ones from 1

Let us assume the room completely painted be 1

Now,

A has done 1/3, B has done 1/4 and C has done 1/5 work of the remaining

So, let us add them

• A + B + C

• ⅓ + ¼ + ⅕

Getting the L.C.M. The L.C.M of 3,4,5 is 60

• 20/60 + 15/60 + 12/60

• 47/60

Hence, 47/60 room has been painted

Remaining to paint

Total is assumed as 1

Work done = 47/60

Fraction of room needs to painted = 1 - 47/60

• (60 - 47)/60

• 13/60

13/60 of the room needs to be painted, OPTION C IS CORRECT