6 is 90% of what number

Question

Sheri has 6 half dollers which is 90% of the half dollers. Justin has the other 10% of half dollers so how many half dollers does justin have

Answer 1

"is" means =

"%" means /100

"of" means *

"what number" means x

6 = 90/100 * x

6 * 100/90 = x

x = 600 / 90

x = 60 / 9

x = 20 / 3

x = 6 2/3

The problem is actually impossible- no solution- because there are 6 2/3 half dollars.  Since we appear to be talking about coins, we can't have a fractional coin.  The math works out that there are a total of 6 2/3 half dollars (Justin would have 2/3 of a half dollar), but since we can't have 2/3 of a coin. . .