Rate and average Problem

Kaunteya wrote:A car averages 25 mpg in the city and 40 mpg on the highway. According to these rates which of the following is the closest to the number of mpg that the car averages when it drives 10 miles in the city and 50 miles on the highway.

a. 28
b. 30
c. 33
d. 36
e. 38

In the city the car used 10/25 gallons of gas (2/5) and on the highway it used 5/4 gallons. Added together you get 8/5 gallons used over the total 60 miles journey. Then to figure out the mpq divide the total miles driven (60) by the total gas consumed (8/5). Now you get 300/8. This is equal to 37.5. Why then is the answer 36 and not 38. Why was the 37.5 mpg not rounded up to 38 but down 1.5 mpg to 36? Are you not to round up?? I don't know, help please.

Kaunteya

Kaunteya wrote:A car averages 25 mpg in the city and 40 mpg on the highway. According to these rates which of the following is the closest to the number of mpg that the car averages when it drives 10 miles in the city and 50 miles on the highway.

a. 28
b. 30
c. 33
d. 36
e. 38

In the city the car used 10/25 gallons of gas (2/5) and on the highway it used 5/4 gallons. Added together you get 8/5 gallons used over the total 60 miles journey. Then to figure out the mpq divide the total miles driven (60) by the total gas consumed (8/5). Now you get 300/8. This is equal to 37.5. Why then is the answer 36 and not 38. Why was the 37.5 mpg not rounded up to 38 but down 1.5 mpg to 36? Are you not to round up?? I don't know, help please.

Kaunteya

igo8 wrote:129- On a recent trip, Cindy drove her car 290 miles, rounded to the nearest 10 miles, and used 12 gallons of gas, rounded to the nearest gallon. The actual number of miles per gallon that Cindy’s car got on this trip must have been between

a) 290/12.5 and 290/11.4
b) 295/12 and 284/11.4
c) 284/12 and 295/12
d) 284/12.5 and 295/11.4
e) 295/12.5 and 284/11.4


The answer says it is D, but that doesn't make sense if you actually round up since 12.5 would go to 13 rounded to the nearest mile and 295 would go 300 if rounded to the nearest 10 miles. Are you not to round up in the GMAT when it is 5???