Question

carlos and maria drove a total of 197 miles in 3.8 hours. carlos drove the first part of the trip and averaged 55 miles per hour. maria drove the remainder of the trip and averaged 47 miles per hour. for approximately how many hours did maria drive? round your answer to the nearest tenth if necessary. a. 2.8 hours b. 2.1 hours c. 1.5 hours d. 2.3 hours

Answer 1

Carlos driving time = Xh, Maria driving time = Yh.
55m/h*Xh + 47m/h*Yh = 197m
Together, they both drove 3,8 hours, so Carlos drove 3,8 hours minus the time Maria drove;
55m/h*(3,8h-Yh)+47m/h*Yh = 197m
55m/h*3,8h - 55m/h*Yh + 47m/h*Yh = 197m
209m - 8m/h*Yh = 197m
8mY = 209m - 197m
8mY = 12m
Y = 12m/8m
Y = 1,5
The correct answer is 1,5 hours.