22 sandwiches and 2 sizes of baskets. One type holds 7 sandwiches and the other holds 4 sandwiches. If a=7 and b=4, which shows the way to carry the sandwiches?

Question

5b
2a + 2b
3a
1a + 3b

Answer 1

If you did not have answers you could set up an equation and make a table of values.

7x+4y=22 where x and y are the two basket sizes.

x=1 means 7(1)+4y=22, 4y=15, no

x=2 means 7(2)+4y=22, 4y=8, y=2, yes

x=3 means 7(3)+4y=22, 4y=1, no

if a=7 and b=4 the answer is 2a+2b

Answer 2

a = 7

b = 4

 

Plug in a=7 and b=4 into each expression and compute the answer:

 

5b = 5*4 = ??

 

2a + 2b = 2*7 + 2*4 = 14 + 8 = ??

 

3a = 3*7 = ??

 

1a + 3b = 1*7 + 3*4 = 7 + 12 = ??

 

Which expression adds up to 22 sandwiches?