She has 90 markers because 18 times 5 is 90
Answer:
<em>8.5</em>
Step-by-step explanation:
To find mean, we simply take the average of all the numbers in the data set, and divide in by the amount of values!

68 ÷ 8 = 8.5!
1,000. 4,200 / 21 = 200. 5 * 200 = 1,000
To solve, simply do this:

Then you'll get the answer, -7/16