An amusement park charges a $20 admission fee and $3 for each ride. which equation can be used to determine c, the total cost of a day at the amusement park, based on n, the number of rides?
n = 3c + 20
n = 20c +3
c = 3n + 20
c = 20n + 3

c = 3n + 20

Step-by-step explanation:

Every ride adds $3, so for n rides you pay 3n. There is only one answer that has 3n in it. And it is the correct one because it adds the fixed $20 for admission.

salary

step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional