One week a computer store sold a total of 36 computers and external hard drives. The revenue from these sales was $22,435. If computers sold for $1180 per unit and hard drives for $125 per unit, how many of each did the store sell?
You need to use the following notations for computers and hard drives, such that:
x represents the number of computers
y represents the number of hard drives
Since the problem provides the information that the computer store sold a total of 36 computers and external hard drives , in one week, you can put the statement into the following mathematical equation, such that:
`x + y = 36 => x = 36 - y`
Since the problem provides the information that computers were sold for `$1180` per unit and hard drives for `$125` per unit and the revenue from these sales was `$22,435` , yields:
`1180x + 125y = 22,435`
You need to replace `36 - y` for` x` in the equation `1180x + 125y = 22,435` , such that:
`1180(36 - y) + 125y = 22,435`
`42,480 - 1180y + 125y = 22,435`
`1055y = 42,480 - 22,435 => 1055y = 20045 => y = 19`
`x = 36 - 19 => x = 17`
Hence, evaluating how many computer and hard drives the store sold, yields x = 17 (computers) and y = 19(hard drives).