How many ounces of 20% hydrochloric acid and 70% of hydrochloric acid must be mixed to make 20 ounces of 50% hydrochloric acid?

Question

What equations can you create to solve this problem?

Answer 1

(X oz)(20%) + (20-x oz)(70%) = (20 oz)(50%)

20x + 1400 - 70x = 1000

solve for x