Two brothers go to school, and the younger brother goes first. After leaving home for 24 minutes, my brother caught up with him by bike, three times faster than his brother. How many minutes did the e

Two brothers go to school, and the younger brother goes first. After leaving home for 24 minutes, my brother caught up with him by bike, three times faster than his brother. How many minutes did the elder brother catch up with the younger brother? 24/(3- 1)= 12 (point)

A: It takes 12 minutes.

This is solved in proportion and does not require speed. Are you clear?

Here's another way:

Let the brother's speed be 100m/min and the brother's speed be 300m/min.

100 * 24/(300-100) =12 (point)

This is also the right thing to do.

If you don't understand, set X, and you can be eliminated in the end.