Question 15 [1 point] Listen A computer screen saver is an expanding circular pattern. The circle starts as a dot, then expands outwards as it grows over time. With a 21" screen, you have a viewing area with a 10" radius (measured from the centre of the screen to a corner]. The screen reaches the corners in exact|y4 seconds. Express the radius of the circle as a function of time. Question 16 (1 point) Listen A coffee shop is selling their donuts for $1. In an average week they sell 300 donuts. For every $0.05 increase in price, the coffee shop will sell 20 less items. Which of the following revenue functions with respect to price increase is correct?Question 17 [1 point] Listen A computer screen saver is an expanding circular pattern. The circle starts as a dot, then expands outwards as it grows over time. With a 21" screen, 1you have a viewing area with a 10" radius (measured from the centre of the screen to a corner]. The screen reaches the corners in exactlvti seconds. Express the area of the circle as a function of time: Question 18 (1 point) Listen You make a purchase at a local furniture store that is too large to take home yourself. For a small fee, the store will deliver your purchase. For your purchase, you pay for the item, the tax and the delivery fee. Taxes are at 14% and the delivery fee is $20. If x represents the price of the item, A(x) represents the total amount for the item, an expression that represents the total amount to be paid for a delivered item, including taxes (assuming that the delivery fee is to be taxed) is:Question 20 [1 point] Listen The cost of fuel in C dollars is a function of the number of litres {L} of fuel consumed. The cost of fuel is $1.01 per litre. The amount of fuel consumed (L) is a function of the number of hundreds of km [K] travelled. A car consumes 12.4 L per 100 km. The equation for the cost of fuel based on the number of hundreds of km travelled is