Please help me. :( thanks

Hillel is juggling flaming torches to raise money for charity. his initial appearance raises $500\$500 $500 , and he raises $15\$15 $15 for each minute of juggling performance. the amount rr r of money hillel raises is a function of tt t , the length of his performance in minutes. write the function's formula.

What is the average rate of change for this function for the interval from x=2 to x=4 ?

If you are dealt 4 cards from a shuffled deck of 52? cards, find the probability that all 4 cards are diamondsdiamonds.