PREP-T2-PS-Q91

[GC06]

A certain car averages 25 miles per gallon of gasoline when driven in the city and 40 miles per gallon when driven on the highway. According to these rates, which of the following is closest to the number of miles per gallon that the car averages when it is driven 10 miles in the city and then 50 miles on the highway?

(A) 28
(B) 30
(C) 33
(D) 36
(E) 38

答案是D
我完全看不懂題目= =
請求幫忙

[Enriqueta]

driven 10 miles in the city=> use 10/25 gallon of gasoline=0.4 gallon
driven 50 miles on the highway=> use 50/40 gallon= 1.25 gallon
Total gasoline used= 1.65 gallon
Total miles= 10+50= 60 miles
Average= 60/1.65= 36

A certain car averages 25 miles per gallon of gasoline when driven in the city and 40 miles per gallon when driven on the highway. According to these rates, which of the following is closest to the number of miles per gallon that the car averages when it is driven 10 miles in the city and then 50 miles on the highway?

(A) 28
(B) 30
(C) 33
(D) 36
(E) 38

答案是D
我完全看不懂題目= =
請求幫忙