Respuesta :
Answer: Manuela must make $11 dollars during the fourth hour
Step-by-step explanation:
In order to calculate the amount of dollars for the fourth hour, you have to calculate the amount of dollars she needs to make in the full four hours:
The average is the amount of dollars earned in 4 hours between the 4 hours. Let A be the average and d be the amount of dollars
A= d/4
A= $8. Replacing A in the expression:
8=d/4
Multiplying by 4 each side:
d=32
Now, if she must make $32 in four hours to average $8 but she already earned $21 in three hours then in the last hour she must make:
$32 - $21 = $11