Answer:
In an hour, Alex can wash 14 windows.
Explanation:
10 1/2 windows per 3/4 hour
per usually means a / sign because you are finding the unit rate
10.5/0.75 (I just converted everything into a fraction to make it easier)
solve:
10.5/0.75 = 14
Another way to solve:
10 1/2 / 3/4
= 21/2 * 4/3
= 21*4/2*3
= 84/6
= 14
Check:
If Alex washes 14 windows per hour, you can check by multiplying 14 by 3/4 of an hour
14*3/4
=42/4
=10.5
10.5 is the same as 10 1/2