10. Total cost = $51 Remove cost for parking $51 - 6 = $ 45 (this price includes the cost of general admission tickets and riding passes) $3.50 + $5.50 = $9 $ 45/ $9 = 5 There were 5 people in the family.
11. Let the number be 'n' 5n - 18 - 4n = -36 n = -36 + 18 = -18 The number is -18