Question

If 3 workers can paint a room in 2 hours, then approximately how long does it take 4 workers to paint the same room? Assume the time needed to paint the room is inversely proportional to the number of workers.

Answer 1

It takes 1.5 hours for 4 workers to paint the same room

Solution:

Given that 3 workers can paint a room in 2 hours

To find: Time taken for 4 workers to paint the same room

Assume the time needed to paint the room is inversely proportional to the number of worker

$time \propto \frac{1}{\text { number of workers }}\\\\time =k \times \frac{1}{\text { number of workers }}$

Where, "k" is the constant of proportionality

3 workers can paint a room in 2 hours

Substitute number of workers = 3 and time = 2 hours

$time =k \times \frac{1}{\text { number of workers }}\\\\2 = k \times \frac{1}{3}\\\\k = 6$

Therefore,

$\text {time}=6 \times \frac{1}{\text { number of workers }}$

To find time taken for 4 workers to paint the same room, substitute number of workers = 4 in above expression

$time = 6 \times \frac{1}{4} = 1.5$

Thus it takes 1.5 hours for 4 workers to paint the same room

Answer 2

Answer:

1.5 hours.............