Aruna K. answered 02/13/17
Tutor
New to Wyzant
Experienced & National Board Certified Chemistry Teacher
The ratio of 5/2 indicates that for every 5 Red bricks 2 Gray bricks are used which means 5 red bricks out of 7 total bricks.
Set it as a proportion
(5/7) x 175 = 125
Hope this helps.