Help please!! i’m confused

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?

Me find the value of x each figure.