Question

The ratio of cars to trucks is 9:4. The ratio of trucks to SUV's is 12:21. There are 54 cars.

Part A: How many trucks are there?
Part B: How many SUV's are there?​

Answer 1

Number of trucks = 24

Number of SUVs = 24

Explanation:

A)

The ratio of cars to trucks is 9:4

The total ratio of cars to trucks is

9+4 = 13

Let x = sum of cars and trucks.

There are 54 cars. Therefore,

x = 54 + t trucks

Number of cars = ratio of cars/ total ratio × sum of cars and trucks. This means,

54 = 9/13 × x

9x / 13 = 54

9x = 13 × 54

9x = 702

x = 702 / 9 = 78

x = 54 + t trucks = number of trucks = 78 = 54 + t trucks

t trucks = 78 - 54 = 24

Number of trucks = 24

B)

The ratio of trucks to SUVs is 12:21

The total ratio of cars to trucks is

12 + 21 = 33

Let y = sum of trucks and SUVs

There are 24 trucks. Therefore,

x = 24 + s SUVs

Number of trucks = ratio of trucks / total ratio × sum of trucks and SUVs. This means,

24 = 12 / 33 × y

12y / 33 = 24

12y = 24 × 33

12y = 792

y = 792 / 12 = 66

y = 24 + s SUVs

66 = 24 + s SUVs

s SUVs = 66 - 24 = 42

Number of SUVs = 24