Karina uses the system of equations below to compare the monthly utility costs in July and December for electricity, x, and natural gas, y.

750x + 17y = 141.61

300x + 30y = 75.90

Karina solves the system using linear combination and arrives at the equation 116y = 96.28. She then solves this equation for y. Which statement explains Karina's solution?

The cost of electricity is $0.17 per unit.

The cost of natural gas is $0.20 per unit.

The cost of electricity is $0.72 per unit.

The cost of natural gas is $0.83 per unit.

Question

Mathematics

Amaya Pham

28 December, 22:51

Karina uses the system of equations below to compare the monthly utility costs in July and December for electricity, x, and natural gas, y.

750x + 17y = 141.61

300x + 30y = 75.90

Karina solves the system using linear combination and arrives at the equation 116y = 96.28. She then solves this equation for y. Which statement explains Karina's solution?

The cost of electricity is $0.17 per unit.

The cost of natural gas is $0.20 per unit.

The cost of electricity is $0.72 per unit.

The cost of natural gas is $0.83 per unit.

+5

Answers (1)

Know the Answer?

Sylvia Harmon · Answer 1

The statement that explains Karina's solution is

The cost of natural gas is $0.83 per unit.

Furthermore, the cost of electricity is $0.17 per unit.

The solution can also be determined by elimination or substitution. Others methods such as the Gauss-Jordan can be used as well.