Marco jumped rope for 20 more seconds than Troy.

The letter r represents the number of minutes that Troy jumped rope.
Which expression shows the number of minutes that Marco jumped rope?

To find the expression that shows the number of minutes that Marco jumped rope, let's break down the information given in the problem:

1) Marco jumped rope for 20 more seconds than Troy.
2) The letter r represents the number of minutes that Troy jumped rope.

First, let's convert the 20 additional seconds to minutes. There are 60 seconds in a minute, so 20 seconds is equal to 20/60 = 1/3 minutes.

Since r represents the number of minutes that Troy jumped rope, Troy's jump rope time can be expressed as r minutes.

To find Marco's jump rope time, we add the extra 1/3 minutes to Troy's time. The expression that represents the number of minutes Marco jumped rope is: r + 1/3.

Therefore, the expression that shows the number of minutes Marco jumped rope is r + 1/3.

r+20/60 = r + 1/3 = (3r+1)/3