Question

Two families go to a theatre

The smith family of three adults and four children pay£67.
The jones family of five adults and six children pay £106

Answer 1

children = £8.5

adults = £11

Explanation:

5 (3a + 4c = 67)

-3 (5a + 6c = 106)

15a + 20c = 335

-15a - 18c = -318

2c = 17

c = £8.5

3a + 4 x 8.5 = 67

3a + 34 = 67

3a = 33

a = £11

Answer 2

5 (3a + 4c = 67) -3 (5a + 6c = 106)

15a + 20c = 335

-15a - 18c = -318

_____________________

2c = 17

divide both sides by 2

c = £8.5

substitute c for 8.5 to find a

3a + 4 * 8.5 = 67

3a + 34 = 67

subtract 34 from both sides

3a = 33

divide both sides by 3

a = £11

thanx

helps