First, put the numbers in order...very important
301,305,310,317,325,328,345,361,362,394
minimum (smallest number) = 301
Q1 = 310
Q2 (middle number) = (325 + 328)/2 = 653/2 = 326.5
Q3 = 361
maximum (largest number) = 394
To solve this problem you have to set up a proportion. To form one side of the proportion you use "is over of" meaning what number represented by is, in this case 18, is placed over the number represented by of, 3000.

Since you are finding the percent of something, youre x value is placed above "100" because percent values are most commonly out of 100%.
So now your proportion will look like


To solve the proportion you cross multiply and divide. So you multiply 100 and 18 since they are crossed from each other, then divide 1800 by 3000. The answer is .6. 18 is .6% of 3000.
First you add 2000 and 500 and then when you get the answer you add 6 and 12 then you get the answer