Question

Linda and Carrie made a trip from their hometown to a city about 200 miles away to attend a friend's wedding. The following chart shows their distances, stops and times. What part of their total trip did they spend driving?
3hr(driving)                            A=4/5               
15min( rest stop)                   B=2/5
1 and 1/2hr(driving)                      C=58/73
1hr(rest stop)                         D=99/100
20min(driving) 

Answer 1

The correct answer is C) 58/73.

We first add up the amount of time spent driving:
3 + 1 1/2 + 20 minutes

Changing 20 minutes to a fraction of an hour, 20/60 = 1/3:
3 + 1 1/2 + 1/3

Using the LCD (6), 
3 + 1 3/6 + 2/6 = 4 5/6 hrs driving.

Now we find the total time of the trip:
3 + 15 min + 1 1/2 + 1 + 20 min
= 3 + 15/60 + 1 1/2 + 1 + 20/60
= 3 + 1/4 + 1 1/2 + 1 + 1/3

The LCD for this is 12:
3 + 3/12 + 1 6/12 + 1 + 4/12 = 5 13/12 = 6 1/12

We find the ratio of driving to total time, which is (4 5/6)/(6 1/12)
= 4 5/6 ÷ 6 1/12

Converting the mixed numbers to improper fractions,

29/6 ÷ 73/12 = 29/6 × 12/73 = 348/438 = 174/219 = 58/73