Respuesta :

Alex worked 5 hours

Explanation:

Amount Alex earns per hour = $3

let the number of hours worked = h

Total amount earned = $15

Total amount earned = Amount Alex earns per hour × number of hours worked

15 = 3(h)

15 = 3h

divide both sides by 3:

15/3 = 3h/3

h = 5

Hence, Alex worked 5 hours