1/2, 7/12 ,2/3,3/4 what’s the next fraction ?

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items