Amount of Interest Earned in a Year
Date: 11/28/95 at 14:17:17 From: Anonymous Subject: hard math If Li Fong had earned one fourth of a percent more in annual interest on an investment, the interest for one year would have been $45 greater. How much did she invest at the beginning of the year?
Date: 11/28/95 at 15:54:36 From: Doctor Ken Subject: Re: hard math Hello there! I think that the hardest part of this question is figuring out the equation you have to solve. Essentially, that means translating the words in the problem into mathematical symbols so that you can work with them. I'll help you through it: One percent is 1/100, so 1/4 of 1 percent is 1/4 * 1/100 = .25 * .01 = .0025 So let X equal the amount of money Li Fong invested, and let P be the percentage rate (something like 1.04 for 4% or something like that). Then the first part of the equation is this: X(P + .0025) That's 1/4 of a percent more interest. Then the whole phrase "the interest for one year would have been" just means "=". So we have X(P + .0025) = XP + 45 because XP is the actual amount she ended up with at the end of a year, and raising the interest would have made that $45 more. Now that you have that equation, you can just solve for X! Good luck. -Doctor Ken, The Geometry Forum
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