Finding ratios word problems

Question

A teacher had 18 red pens. If the ratio of red pens to blue pens she owned was 3:5, how many pens did she have total?

Answer 1

3/5 = 18/? There are six 3's in 18. To keep the ratio you must multiple the denominator by 6... 5X6 equals 30.

Or....the ratio is 3/5 = 60% 18 divided by the ratio 60% equals 30

Answer is 30