Question

The cost of 3 sandwiches and 2 cookies is £8 .

the cost of 7 sandwiches and 2 cookies is £16.

How much does a sandwich cost?
How much does a cookie cost?

Answer 1

Sandwich=£2

Cookie=£1

Explanation:

3s+2c=8

7s+2c=16

What changes?

The number of sandwiches, and total £.

If we take cookies out of the equation, we get:

3s=8

7s=16

The difference is:

4s=8

Solve: 4s=8

s=2

So if s=2, then just substitute and solve to find c:

3s+2c=8

6+2c=8

2c=2

c=1

Answer 2

£2and£1

Explanation:

the sandwiches cost £2 and the cookie cost £1