Lindsay can paint 1/x of a certain room in 20 minutes. what fraction of the same room can joseph paint in 20 minutes if the two of them can paint the room in an hour, working together at their respective rates?
a) 1/3x
b) 3x/x-3
c) x-3/3x
d) x/x-3
e) x-3/x

Step-by-step explanation:

Lindsay can paint 1/x of a certain room in 20 minutes.

1 hour = 3 times 20 minutes

rate of work by Lindsay in 20 minutes is

Let 't' be the work done by Joseph

rate of work by Joseph in 20 minutes is

Both completed the work in 1 hour

solve the equation for 't'

Subtract 3/x on both sides

cross multiply it

Divide both sides by x-3

Work done together is

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls