13. The Cyclone Coaster has 16 cars. Some of them hold 2
passengers and some hold 3
passengers. If there is room for
36 people altogether, how many
cars hold 3 passengers?

Four cars that can hold 3 passengers

Step-by-step explanation:

The number of cars on the Cyclone Coaster = 16 cars

The number of passengers some cars hold = 2 passengers

The number of passengers the other cars hold = 3 passengers

The number of people altogether the Cyclone Coaster has room for = 36 people

Let x represent the number of cars that can hold 3 passengers, and let y represent the number of cars that can hold 2 passengers, we have;

3·x + 2·y = 36...(1)

x + y = 16...(2)

The value of x can be found by making y the subject of equation (1) and equation (2) and equating both values of y given in x as follows;

The value of y from equation (1) is, y₁ = (36 - 3·x)/2 = 18 - 3·x/2

∴ y₁ = 18 - 3·x/2

The value of y from equation (2) is, y₂ = 16 - x

Equating both y values, to find the coordinates of the common point to both equations, gives;

At the common point y₁ = y₂

By the substitution property of equality

∴ 18 - 3·x/2 = 16 - x

3·x/2 - x = 18 - 16 = 2

x/2 = 2

∴ x = 4

The number of cars that can hold 3 passengers, x = 4

(From y₂ = 16 - x, we have

y₁ = y₂ = 16 - 4 = 12

y = 1

The number of cars that can hold 2 passengers, y = 12).