Carcass wrote:
A machine can be repaired for $1,200 and will last for one year, while the new machine would cost for $2,800 and will last for two years. The average cost per year of the new machine is what percent greater than the cost of repairing the current machine ?
(A) 7%
(B) 10%
(C) 16.67%
(D) 18.83%
(E) 20%
Ok, there is a lot going on in this problem, so it would be best to take things one step at a time and make sure we understand all the details.
Reading through the problem once, we learn that we need to find the average cost per year of both the new machine and compare it with the average cost per year of repairing the old machine:
New Machine --->
$2800/
2 years ===>
average cost per year =
$1400Old Machine ---->
$1200/
1 year ===>
average cost per year =
$1200Now, we need to find what
percent greater the average cost per year of new machine is compared to maintaining the old machine:
A cool mnemonic for percent change is new minus old over old ----> (
new -
old) /
oldApplying it to this problem, we get:
[(
average cost per year of new machine) - (
average cost per year of old machine)] / (
average cost per year of old machine)
Plug in the information from the problem:
(
1400 -
1200) /
1200 =
200 /
1200 =
1/
6 =
.1666Multiply by 100 to get the percentage:
(
.1666)(
100) =
16.66% greater, which rounds up to 16.67% ----->
Answer Choice C