Which of the following options best describes an algebraic fraction?
select all that apply.
1.) common denominators
2.) a variable in the numerator
3.) a variable in the denominator
4.) a variable with an exponent.
i already know 4 for sure is

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?