From the question given,
Area of the parking lot = 300 square meters
Bicycle requirement = 3 square meters
Bus requirement = 9 square meters
Total number of vehicle = 40 vehicles
Let x be the number of bicycles and y be the number of bus
x + y = 40 -------------------------(1)
3x + 9y = 300 ---------------------------(2)
We can solve by elimination method
Multiply through equation (1) by 3 in other to eliminate x and then we will solve for y
3x + 3y = 180----------------------------(3)
Equation (2) - Equation (3)
6y = 180
Divide both-side by 6
y = 30
substitute y=30 into equation (1) and solve for x
x + 30 = 40
subtract 30 from both-side
x = 40 -30
x=10
Number of bicycle is 10 and number of bus is 30
Since, a bicycle is charged $1.50 and bus is $3
Then the total income is;
$(10 × 1.50 + 30 × 3)
= $(15 + 90)
= $105
Therefore, the the possible income region is $105.