Question 1027311
In 1 hour Nina can wash 1/2
In 1 hour Mark can wash 1/5
Find common denominator:
1/2 multiply times 5 = 5/10
1/5 multiply times 2 = 2/10
5/10+2/10 = 7/10
1 hour has 60 minutes:
7/10*60/1 = 420/10 = 42 minutes is your answer