The ratio of girls to students at a middle school is 10 to 18. if there are 270 students at the school, how many are girls?
100
150
180
200
(i believe its 150, but i'm not sure. it'll be awesome if you can explain how to do this also)

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?