| no. of bags | % as | no. of bags of | of pre-mix |decimal| pure cement ------------|--------------|-------|--------------- 4% cement| x | 0.04 | 0.04x ------------|--------------|-------|--------------- 11.6% cement| 10 |0.116 | 0.116(10) ------------|--------------|-------|--------------- 8% cement| x+10 | .08 | 0.08(x+10) 0.04x + 0.116(10) = 0.08(x+10) Solve to get answer Edwin