Question 1008357
Assuming the aggregate is pure 100% aggregate, then let x be the amount of 60% aggregate you start with. Then:
.6x+1(48-x)=48(.75)
.6x+48-x=36
12=.4x
x=12/.4=30
30 ks of 60% aggregate mixed with 18 ks of pure aggregate make 48 ks of 75% aggregate!!!!!!!