Rounding Rules

[torofish]

Andrew drove his truck 100 miles, rounded to the nearest 10 miles, and used 10 gallons of gasoline, rounded to the nearest gallon. The actual number of miles per gallon that Tom's truck got on this vacation trip must have been between

A 100/10.5 and 100/9.5
B 95/10.5 and 105/9.5
C 95/9.5 and 105/10.5
D 105/10 and 95/9.5
E 105/10.5 and 95/9.5

OA: B

What I wonder the most is the rounding rule.

To be rounded to 10, isn't it 10.4, 10.3, 10.2, 10.1 10 9.9 9.8 9.7 9.6 9.5

If it's XXX.5, we will round up.

But here 10.5 is rounded down to 10.
Isn't supposed to be rounded up to 11?

[kevincanspain]

Think a little more about the word 'between'-

[Makushr1]

Andrew drove his truck 100 miles, rounded to the nearest 10 miles, and used 10 gallons of gasoline, rounded to the nearest gallon. The actual number of miles per gallon that Tom's truck got on this vacation trip must have been between

A 100/10.5 and 100/9.5
B 95/10.5 and 105/9.5
C 95/9.5 and 105/10.5
D 105/10 and 95/9.5
E 105/10.5 and 95/9.5

OA: B

What I wonder the most is the rounding rule.

To be rounded to 10, isn't it 10.4, 10.3, 10.2, 10.1 10 9.9 9.8 9.7 9.6 9.5

If it's XXX.5, we will round up.

But here 10.5 is rounded down to 10.
Isn't supposed to be rounded up to 11?

For this type of question, look for the smallest and largest answers. Out of 95 and 105 miles and 9.5 and 10.5 gallons, the largest mpg you could get would be diving the largest miles by smallest gallons, so 105/9.5. The smallest ratio would be least miles, 95, divided by largest use of gallons, 10.5.

Dont even worry about rounding, all but 1 answer uses 105/95 and 9.5/10.5. just find the largest variance.