Question

Lakisha had 10 dollar bills and 1 bills in her wallet. She used seven bills to buy a pair of shoes for 43 dollars. How many of each type of did she spend?

Answer 1

Answer: she spent three 1 dollar bills and and four 10 dollar bill.

Step-by-step explanation:

Let x represent the number of 1 dollar bills that she used.

Let y represent the number of 10 dollar bill that she used.

She used seven bills to buy a pair of shoes. This means that

x + y = 7

The amount that she spent on the pair of shoes is $43. This means that

x + 10y = 43 - - - - - - - - - - 1

Substituting x = 7 - y into equation 1, it becomes

7 - y + 10y = 43

- y + 10y = 43 - 7

9y = 36

y = 36/9 = 4

x = 7 - y = 7 - 4

x = 3