Please answer for me

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

Reinel saves 30% of every pay check. his paycheck last week was 560$. how much did reniel save last week?

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.