Answer:
9
Step-by-step explanation:
Let us represent
Low priced = x
High priced = y
An online store sells two types of speaker docks for smartphones. The higher-priced speaker dock sells for $170 and the lower-priced speaker dock sells for $90. Combined sales totaled $4,770.
170x + 90y = $4770
Last week the store sold four times as many lower-priced speaker docks as higher-priced speaker docks.
4x = y
Substitute 4x for y
170x + 90y = $4770
170x + 90(4x) = $4770
170x + 360x = $4770
530x = $4770
x = 4770/530
x = 9
The number of lower-priced speaker docks it sold was 9