Actual distance of the Harper from the school = 50 yards.
According to map the distance from the school = 34 inch.
We could say 34 inches represents 50 yards.
So, 1 inches could be represented by 50/34 = 25/17 yards.
In order to find the actual length of 3 inches in yards, we need to multiply 1 inches value of yards by 3.
Therefore, 3 inches = 3* 25/17 = 75/17 = 4 7/17 yeards in decimals 4.412 yards approximately.
Therefore, Harper from home is 4 7/17 yeards or 4.412 yards approximately if the map shows the distance as 3 inches.