Answer:
Option d is correct
The cost of natural gas (y) = $0.83 per unit
Step-by-step explanation:
Given the system of equation:
750x + 17y = 141.61 ......[1]
300x + 30y =75.90 ......[2]
where x is the cost of electricity and y is the costs of natural gas.
Multiply equation [1] by 30 and equation [2] by 75 we get;
[tex]30 \cdot (750x + 17y) = 30 \cdot 141.61[/tex]
Simplify:
22500x + 510y = 4248.3 ......[3]
[tex]75 \cdot (300x + 30y) = 75 \cdot 75.90[/tex]
Simplify:
22500x + 2250y = 5692.5 .......[4]
Subtract equation [3] from [4] we get;
1740 y = 1444.2
Divide by 15 both sides, we get
116 y = 96.28
Since, Katrina solves the above system using linear equation and arrives at the equation :
116 y = 96.28
Division property of equality states that divide the same number to both sides of an equation:
Divide by 116 to both sides of an equation, to solve for y;
[tex]\frac{116 y}{116} =\frac{96.28}{116}[/tex]
Simplify:
y = 0.83 where y represents the cost of natural gas
Therefore, the cost of natural gas y ,is, $ 0.83 per unit.
