1.Twelve hungry teenagers can devour a very large pizza in 20 minutes. How many teenagers would it take to finish a very large pizza in 15 minutes? (Assume that all teenagers eat pizza at the same rate.)

2.Tina lives 30 miles away from her work, and she normally drives at 45 miles per hour. If she wants to get to work 10 minutes earlier, how fast should she drive to work, in miles per hour?

3.All of the members of our spray-painting team paint at the same speed. If 5 team members can paint a certain wall in 27 minutes, then how many minutes would it take 15 of our team members to paint the same wall?

itachiuchihakujo Jan 5, 2021

#1**+2 **

1.Twelve hungry teenagers can devour a very large pizza in 20 minutes. How many teenagers would it take to finish a very large pizza in 15 minutes? (Assume that all teenagers eat pizza at the same rate.)

This is known as a "see-saw" problem

12 * 20 = 15 * x

12 * 20 / 15 = x

240 / 15 = x

16 teenagers

CPhill Jan 5, 2021

#2**+2 **

2.Tina lives 30 miles away from her work, and she normally drives at 45 miles per hour. If she wants to get to work 10 minutes earlier, how fast should she drive to work, in miles per hour?

Distance / Rate = Time

30 m / ( 45 m/hr) = (30/45) h = 2/3 h = 40 min it takes her to get to work driving at 45 mph

So.....she needs to cover 30 miles in 10 minutes less = 30 min

So....she needs to cover 1 mile per minute = 60 mph

CPhill Jan 5, 2021

#3**+2 **

3.All of the members of our spray-painting team paint at the same speed. If 5 team members can paint a certain wall in 27 minutes, then how many minutes would it take 15 of our team members to paint the same wall?

Let's solve this with some logic

15 team members can do 3 times the work of 5

So....the time it takes them must just be 1/3 of 27 = 9 minutes

CPhill Jan 5, 2021