Help please its a math test about lateral area and surface area help please

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

Alocal hamburger shop sold a combined total of 601 hamburgers and cheeseburgers on friday. there were 51 more cheeseburgers sold than hamburgers. how many hamburgers were sold on friday? a local hamburger shop sold a combined total of hamburgers and cheeseburgers on friday. there were more cheeseburgers sold than hamburgers. how many hamburgers were sold on friday?

Given lm, find the measure of (award brainliest)