Question

It takes 28 minutes for 7 people to paint 7 walls.

Answer 1

Answer: 28 minutes

Step-by-step explanation:

If M1 men can do W1 work in working H1 hours per day and M2 men can do W2 work in working H2 hours per day (where all men work at the same rate), then

$\frac{M_1H_1}{W_1}=\frac{M_2H_2}{W_2}\\\Rightarrow\frac{7\times28}{7}=\frac{14H_2}{14}\\\Rightarrow\frac{28}{1}=H_2\\\Rightarrow\ H_2=28$

hence, It takes 28 minutes for 14 people to paint 14 walls.

Answer 2

Well, since you have twice as many people and twice as many walls. It would take them also 28 minutes to paint all the walls.
Hope I helped!