```Question 205328
There is a flat rate of \$5 initially plus \$12 for every ticket you purchase. If you buy 2 tickets you still only pay one service fee of \$5 (as long as you buy them in the same transaction and not go back later otherwise you will be charged another service fee). 1 ticket = \$12 + \$5 = \$17, 2 tickets = \$24 + \$5 = \$29, 3 tickets = \$36 + \$5 = \$41, etc. so the total cost goes up by \$12 for every 1 increase in the number of tickets.

The slope is the rate which is the cost per ticket.

It is a bit like buying in bulk – the more you get under one service charge the cheaper each one will be on average since the service charge per ticket will be less. \$17/1; \$29/2; \$41/3; etc. gradually gets less.

There are many things in life which has an initial sacrifice like using the car to go to the supermarket – the journey there and back is fixed irrespective of what you buy – it might be closed and you wasted your journey. The more you buy the more you pay, but you still make the same journey to and from the supermarket irrespective of how much you buy. The journey there and back is the initial sacrifice you make irrespective of what you buy.

Think of temperatures F = 9/5 C + 32; 32 is the freezing point of water and every 1 increase in C results in 1.8 increase in F.```