First, let's simplify it down. We want to find out how many shirts she can fold in 1 minute, then multiply that by 50.
20 shirts in 2.5 minutes
20 shirts = 2.5 minutes
An equals sign is like a see-saw. If you do something to one side, you have to do it to the other side. To get 20 shirts to 1 one shirt, divide by 20. You have to do that to the other side to make it equal.
(20 divided by 20) = (2.5 divided by 20)
1 shirt = 0.125 minutes.
That's how long it takes to fold 1 shirt. To find the time for 50 shirts, multiply that by 50.
0.125 x 50 = 6.25
It will take Carrie 6.25 minutes to fold 50 shirts. Hope this helped =)