Question

An office supply store is selling markers in packages of 2 and packages of 5. If the store sold 7 packages containg a total of 23 markers, how many of the packages contained 2 markers?

Answer 1

4

Explanation:

If all packages contained 5 markers, then 35 markers would have been sold. Instead, a number 12 fewer than that was sold.

The sale of a 2-marker package instead of a 5-marker package reduces the marker count by 3 for each 2-marker package. Hence there were 12/3 = 4 packages of 2 markers sold.

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If you like, you can write an equation for x = the number of 2-marker packages. Then the total number of markers sold was ...

2x +5(7-x) = 23

-3x +35 = 23 . . . . simplify

-3x = -12 . . . . . . . . subtract 35

x = -12/-3 = 4 . . . . divide by 3

4 packages contained 2 markers.