Again pliz help me this question

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.

Agroup of three friends order a combo meal which includes two slices of pizza and a drink each drink is priced at $2.50 the combined total of $31.50 how much is the cost of a slice of pizza

Arational number that is equivalent to -20/4?