Answer:
12.375 miles
Explanation:
The distance between Ian's house and the park is 16 1/2 miles or 16.5 miles. His grandmother lives 3/4 of the way between Ian's house and the park. We need to know what is the 3/4 of such distance. Lets say Ian's house is at mile 0 and the park is at mile 16.5 in a distance line.
We can find the position of his grandma's house by multiplying such distance by 3/4 or 0.75, which is equivalent:
grandma = 16.5 * 0.75 = 12.375
So, on our distance line her grandma is at the position mile 12.375.
As Ian is at the mile 0 and his grandma's house is at 12.375 miles away from Ian's house.