Please Help me Asap

Rob's first four test scores are 80, 85, 100, and 85. What does he have to score on the last test in order to have a test average of 90?
options:

90


100


10


95

Respuesta :

Answer:

100

Step-by-step explanation:

Given Average After writing a last test=90

let the last test score be x

Now given

[tex] \frac{80 + 85 + 100 + 85 + x}{5} = 90[/tex]

[tex]80 + 85 + 100 + 85 + x = 450[/tex]

[tex]x + 350 = 450[/tex]

[tex]x = 100[/tex]

I hope it helped you