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

i dont know if you cant find a way its best to actually add all of them start from 105 tho

step-by-step explanation:

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis: