Question

For each problem, identify the variables, write the equations, and solve

Answer 1

Let the 4-passenger cars be represented with F

Let the 6-passenger cars be represented with S

Rocket Coaster has 15 cars

So that F + S = 15 ----- Equation 1

Also, we were told that the total room for 72 passenger

so that 4F + 6S = 72 ----- Equation 2

Solving the two equations simultaneously using the substitution method,

Step 1

From equation 1:

Make F the subject of the formula

F = 15 - S ---- Equation 3

Step 2

substitute equation 3 into equation 2

4 (15 - S) + 6S = 72

Step 3

60 - 4S + 6S = 72

6S - 4S = 72 - 60

2S = 12

divide both sides by 2

S = 12/ 2

S= 6

Step 4

Substitute the value of S = 6 into equation 3

F = 15 - 6

F = 9

So the number of 4-passenger cars = 9

the number of 6-passenger cars = 6