Hong bought a desktop computer and a laptop computer.

Question

Hugh bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $400 less than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was 7.5% per year, and for the laptop it was 8% per year. The total finance charges for one year were $371. How much did each computer cost before finance charges?

Answer 1

Here are your equations and variables:

1. Express the given information:
2. The laptop is $400 less than the desktop. What price is the desktop? You can say that the desktop is "x." In this case, the laptop is "x-400", since it is $400 less than the desktop
3. The finance rates per year are this:
4. First, convert the given finance rates from percentage form to decimal form, by dividing by 100.
5. This makes 7.5% to .075. Eight percent is 0.08.
6. Multiply the price of each computer with the correct yearly finance rate. Remember, we are calculating for one year, so there are no squared items here. Please keep it simple.
7. The desktop: (x)(0.075)
8. The laptop: (x-400)(0.08)
9. Now the last piece of information is the total finance charge for both computers for one year, which is $371.
10. Put all the items, which are called variables, into an equation:
11. (x)(0.075) + (x-400)(0.08) = 371
12. Solve for x.
13. 0.075 x + 0.08x -32 =371
14. 0.155x -32 =371
15. 0.155x = 371 + 32
16. 0.155x = 403
17. x= 403/.155
18. x= 2600
19. The desktop costs $2600. The laptop costs $400 less, or $2200.
20. Check your answer: Plug the numbers in:
21. (2600)(0.075) + (2200)(0.08) = 371
22. 195 + 176 =371
23. 371 = 371 Voila!