Please help me. And please explain.

The equation below shows the relationship between n, the number of minutes of calling time and, c, the charges in dollars for a cell phone plan.

c = 24 + 1/10n
Which table shows the relationship between n and c?

A.

n c
70 31
80 32
90 33

B.

n c
70 33
80 32
90 31

C.

n c
70 724
80 824
90 924

D.

n c
70 7
80 8
90 9

Question

Please help me. And please explain.

The equation below shows the relationship between n, the number of minutes of calling time and, c, the charges in dollars for a cell phone plan.
 
c = 24 + 1/10n
Which table shows the relationship between n and c?

	
A.
 
n	c
70	31
80	32
90	33
	
B.
 
n	c
70	33
80	32
90	31
	
C.
 
n	c
70	724
80	824
90	924
	
D.
 
n	c
70	7
80	8
90	9

anonymous · Answer

$$c=24+n/10$$$$c-24=n/10$$$$n=10(c-24)$$

Now plug in the value of c in the given answers.

Answer A gives you c=31. So the equation is $$n=10(31-24)$$ Which gives you n=70.

Which is correct.

You can check the other answers the same way, and you will find them to be incorrect.