If i can make 60 cakes in 15 minutes , how many can i make per minute what is the unit rate

Henry is an avid reader, he devours 90 pages in half an hour how many pages has henry read per minute?

Can someone explain to me how to do

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.