Answer: John must travel at 43.75 mph
Step-by-step explanation:
Let x represent how fast John should travel in order to catch up with Dina 2 hours after he leaves.
By the time they meet, they would have covered the same distance.
Distance = speed × time
Dina leaves her house driving east at 35 miles per hour. Distance covered by Dina in 2 hrs 30 minutes is
35 × 2.5 = 87.5 miles
Thirty minute later, her husband John notices she forgot her cell phone and sets off after her.
Distance travelled by John in 2 hours is x × 2 = 2x
Since they covered the same distance, then
2x = 87.5
x = 87.5/2 = 43.75
