I am reading the following simple problem on rounding.
Traveling at an average rate of between $60$ and $70$ miles/hour for $3$ to $4$ hours select the best estimate for the distance traveled
a) $90$ miles
b) $190$ miles
c) $225$ miles
d) $275$ miles
I thought the following:
Since it is between $60$ and $70$ and $3$ to $4$ then if we round up/down we have:
$$60 \cdot{3} = 180$$ or
$$70 \cdot{3} = 210$$ or
$$60 \cdot{4} = 240$$ or
$$70 \cdot{4} = 280$$
So it seems to me that the answer should be d since $280 - 275 = 5$ is the smallest difference among with all the other options. But the solution says c.
What am I doing wrong here?