Question 270382
a concrete mix requires 2 parts sand and three parts cement. How manypds are need for 75 pounds of cement? ( guess an varable fraction problem)

The ratio of sand to cement in the concrete mixture is 2/3. Let x be the amount of sand needed to mix with 75 lbs of cement. 

Then we know that:

2/3 = x/75

Multiply both sides of the equation above by 75:

(2/3)*75 = (x*75)/75

50 = x