1 box of crayons and 3 erasers cost 10$. 3 boxes of crayons and 3 erasers cost 18$. How much is 1 box of crayons and 1 eraser

Question

Help!! I can't figure out this answer. I have no idea

Answer 1

c + 3e = 10

3c + 3e = 18

 

Now, there are different ways to solve this...

 

You may notice that the only difference between the two left sides is 2c, so...

 

2c = 8

c = 4

 

4 + 3e = 10

3e = 6

e = 2

 

If you don't see that, solve the first equation for c...

 

c = 10 - 3e

 

Now, substitute into the 2nd equation...

 

3(10 - 3e) + 3e = 18

30 - 9e + 3e = 18

6e = 12

e = 2

 

c + 3(2) = 10

c + 6 = 10

c = 4

 

Hope this helps!