Answer:
Train A - 50 miles per hour
train B - 30 miles per hour
Explanation:
Let x mph be the speed of the train B, then the speed of the train A is (x+20) mph.
In 3 hours,
- train A travels 3(x+20) miles
- train B travels 3x miles
In total, they covered the distance of 240 miles, so
![3(x+20)+3x=240\ \ \ \text{[Divide by 3]}\\ \\x+20+x=80\\ \\2x=80-20\\ \\2x=60\\ \\x=30\ mph\\ \\x+20=30+20=50\ mph](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1dw52a8jeubif95uvrwltttu7rsl0w2ch9.png)