Question 1155927
x*3=3x cost of 1 type. units are $
18*2.50=45 of other type
(18+x)*2.85=51.3+2.85x

3x+45+51.3+2.85x, the amount of the first two equals the total
0.15x=6.3
x=42 pounds 
that cost is $126
18 pounds costs $45

60 pounds costs $171

171/60=$2.85

Answer is 60 pounds