Question

how many gallons of 60% antifreeze solution must be mixed with 60 gallons of 20% antifreeze to get a mixture that is 50% antifreeze

Answer 1

60/100.x + 20/100.60=(x+60).50/100
3/5.x + 12 = 1/2.x +30
3/5.x - 1/2.x = 30-12
1/10.x = 18
x = 180 gallons

Answer 2

60x + 20* (60) = 50* (x+60)
60x + 1200 = 50x + 3000
10x= 3000- 1200 = 1800/10 = 180 which means fatonbina was right....lolzzz :);)