Question

So far this quarter your science quiz scores are: 89 95 85 83 88. You have one more science quiz to take. What do you need to get to make sure you end up with at least a 90% average

Answer 1

`100\:[\%]`

Explanation:

The average of a set of
`n` values is equal to the sum of the values in the set divide by
`n`.

After you take another quiz, you'll have a total of six scores. Therefore, to end up with an average of 90, the sum of all your scores must be at least
`6\cdot 90=540`

Therefore, we can set up the following inequality:

`89+95+85+83+88+n\geq540,\\440+n\geq 540,\\n\geq \boxed{100}`

Therefore, the minimum score you need to get to end up with a 90% average is
`\boxed{100\:\%}`.