# math

posted by .

john bought a bag, pai oh shoes ad a watch for \$160 altogethe. the bag cost \$15 more than the pair of shoes and the watch cost \$20 less than the bag. What was the cost of the bag?

• math -

let x = cost of bag
let y = cost of shoes
let 160 - (x+y) = cost of watch
set up equations:
(1) x = y + 15
(2) 160 - (x+y) = x - 20
solve simultaneously. we can either use elimination or substitution, but for this problem let's just use substitution. we substitute equation (1) to equation (2):
160 - (y + 15 + y) = y + 15 - 20
160 - 2y - 15 = y - 5
-2y - y = -160 + 15 - 5
-3y = -150
y = \$ 50 (cost of shoes)
x = y + 15 = \$ 65 (cost of bag)
160 - (x+y) = \$ 45 (cost of watch)

hope this helps~ :)

## Similar Questions

1. ### math

a 50 pound bag of glossy coat horse feed cost \$23.50. A 25 pound bag cost \$15.50. How much money per pound would you save by buying the bag with the lower unit price?
2. ### math 12

Ryan reaches into his gym bag for a pair of running shoes. If there are seven different pairs of shoes loose in the bag, how many ways can he pick two shoes that do not match?
3. ### math

Ryan reaches into his gym bag for a pair of running shoes. If there are seven different pairs of shoes loose in the bag, how many ways can he pick two shoes that do not match?
4. ### Algebra 1

Ruffles cost \$3.49 per bag. Chips-Ahoy cost \$3.99 per bag. Bobby spent 42.39. If he bought 5 more bags of Chip-Ahoy than Ruffles, how many bags of each snack did he buy?
5. ### Math

Mr. Logan purchased \$390 in clothing (excluding sales tax). He bought 5 identical shirts, 3 identical pairs of pants and 2 identical pairs of shoes. Each pair of shoes cost twice the combined value of one shirt and a pair of pants. …
6. ### Math - Grade 5

A shop sells candies by weight. Monisha bought 2 full bags of chocolates and 3 full bags of gummy bears for \$23.50. If 3/4 of a bag of chocolate cost as much as 5/6 of a bag of gummy bears, find the cost of 1 full bag of chocolates.
7. ### Math

Mrs. Daniel pays \$324 for a handbag and 3 pairs of shoes. The handbag cost half as much as the 3 pairs of shoes combined. Find the cost of the hand bag.
8. ### math

A store sells snacks by weight. A six ounce bag of mixed nuts costs \$3.60. Will a two ounce bag of nuts cost more than or less than \$1.25?
9. ### 8th grade math and algebra class

A bird seed store is running a sale, when as you buy additional bags of seed you get a reduction in price on the additional bags. - first and second bags cost \$20/bag - third through fifth bag cost \$15/bag - sixth through tenth bags …