Step-by-step explanation:
Considering speed of Noha = 4miles per hour
and speed of andrew = 2 miles/hour
The distance between Noha and andrew = 15 miles
Case 1: when they are travelling towards each other( opposite direction)
Then their relative speed becomes = 4+2 = 6miles/hour
Time taken to meet = Distance/relative speed = 15/6 = 2.5 hours
Case2: When they are travelling same direction
Then their relative speed becomes = 4-2 = 2 miles/hour
Time taken to meet = Distance/ relative speed = 15/2 = 7.5 hours
