Question 108327
.9x+.75(1200-x)=.85*1200
.9x+900-.75x=1020
.15x=1020-900
.15x=120
x=120/.15
x=800 is the amount of 90% gas.
1200-800=400 of 75% gas.
proof
.9*800+.75*400=.85*1200
720+300=1020
1020=1020