So i’m trying to divide #13 i just don’t understand how to write it out ..

The ratio of men to women working for a company is 4 to 5 . if there are 90 women working for the company, what is the total number of employees?

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

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