Aldo's scores on four tests are 88, 85, 100, and 86. What must the score be on the fifth test for her average to be 90?

x=5th test score

(88+85+100+86+x)/5=90

(359+x)/5=90

71.8+x/5=90

-71.8              -71.8

x/5=18.2

*5       *5

x=91

the fith test score has to be 91 in order for the average to be 90

wth is with the little mtn top and what are you talking about like fix your words and accually make sence with them and i like was in a completly different question like three times like it seems like your ilitteret