Please help! Need help with question quickly! Thank you so much if you can help! :)

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?