Answer:
8 mph, 12 mph
Step-by-step explanation:
t = Time taken = 7 hours
x = Speed of Randall
x+4 = Speed of Gregory
The distance they both will travel together is 140 miles if they start at the same time.
![Distance=Speed* time](https://img.qammunity.org/2021/formulas/physics/high-school/n7mzv0mge0ludfy2z3bbvwv4zmskr8k0u1.png)
![(x+4)t+xt=140\\\Rightarrow (x+4)7+7x=140\\\Rightarrow 7x+28+7x=140\\\Rightarrow 28+14x=140\\\Rightarrow x=(140-28)/(14)\\\Rightarrow x=8\ mph](https://img.qammunity.org/2021/formulas/physics/high-school/kv89wzn0mm803fstggug7abkkcxwrmhjds.png)
The speed of Randall is 8 mph
The speed of Gregory is 8+4 = 12 mph