Question

On a recent trip to the convenience store, you picked up 3 gallons of milk, 6 bottles of water, and 6 snack-size bags of chips. Your total bill (before tax) was $29.10. If a bottle of water costs twice as much as a bag of chips, and a gallon of milk costs $1.70 more than a bottle of water, how much does each item cost?

Answer 1

Hi

the trick is to define price by referring only to one item.

Here the bootle of water is you reference.

there is 3 gallons of milk

6 bottles of water

6 bags of chips

let's call bottle of water " X"

water cost = X

milk = X+1.7

chips = X/2

So we have :

3 (X+1.7 ) + 6X + 6 ( X/2) = 29.1

3X+ 5.1 + 6X + 6X/2 = 29.1

3X +6X + 3X + 5.1 = 29.1

12X +5.1 = 29.1

12X = 29.1 - 5.1

12 X = 24

X = 24/12

X = 2

price of bottle is 2 dollars

then milk is 2 + 1.7 = 3.7

chips = 2/2 = 1

let's check = 3*3.7 + 6*2 + 6*1 = 11.1+12+ 6 = 29.1