I\'m looking for an equation that will help me prove or disprove that two items

Question

I'm looking for an equation that will help me prove or disprove that two items will be equal in cost over x amount of years.

They may never be equal, I just need an equation to show it either way.
One dishwasher costs $200 and has an energy rating of 350 kWh/y. The second dishwasher costs $400 and has an energy rating of 340 kWh/y. The cost for energy is .1200/kWh.

I see that the second dishwasher is more expensive and has a lower energy rating. This tells me that they will never be equal, I just want to prove it with an equation.

Explanation / Answer

the first dishwasher has a cost of 200 + usage(350) x cost of power(.1200) x yr(y) or: 200 + (350)(.1200)y = 200 + 42y the second dishwasher has a cost of 400 + usage(340) x cost of power (.1200) x yr (y) or: 400 + (340)(.1200)y = 400 + 40.8y setting these = to each other we get : 200 + 42y = 400 + 40.8y subtract 200 from each side: 42y = 200 + 40.8y subtract 40.8y from each side: 1.2y = 200 divide both sides by 1.2: y = 166.6666666 = 166 2/3 yrs (hardly the life expectancy of a dishwasher) Hope that helps! remember to rate, it will help your respect score.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.