Question

It takes 212121 minutes for 555 people to paint 777 walls. How many minutes does it take 333 people to paint 555 walls?

Answer 1

Solution: We are given that:

5 people can paint 7 walls in 21 minutes

Therefore, 1 person can paint 7 walls in $21 \times 5=105$ minutes

Which means 1 person can paint 1 wall in $\frac{105}{7} =15$ minutes

Now, 3 people can paint 1 wall in $\frac{15}{3} =5$ minutes

Therefore, 3 people can paint 5 walls in $5 \times 5=25$ minutes