Question

Lisa's test grades are 79, 89 and 90

b. There will be one more test this year. If Lisa wants her test average to at least be 88, what is the lowest grade she could get on her last test.

Answer 1

• Mean=Sum of data/No of data

So

Let that be n

• n+79+89+90/4=88
• n+258/4=88
• n+258=352
• n=94

Answer 2

94

Explanation:

Equating the mean to the scores :

• 88 = 79 + 89 + 90 + x / 4
• 352 = 258 + x
• x = 94