Question

A woman went marketing for sugar for canning. In one store, sugar was 8 1/2¢ per pound and she found that she lacked 30¢ of having enough money to buy the number of pounds she needed. She bought the required amount of sugar at another store for 8¢ per pound, and had 45¢ left. How much money did she have before making the purchase?

Answer 1

x=amount of money woman has
n=pounds of sugar
Store #1: 8.5*n=x+30
Store #2: 8*n=x-25

multiply #2 by 17/16 to make coefficient of n same as in #1

2: 8.5*n=17/16(x-25)

Subtract #2 from #1

0=x+30-17/16(x-25)
x+30-17x/16 +25*17/16
x/16=30+25*17/16
x=480+425
=905 cents
=$9.05