We are still finishing Pre Algebra. For #5 of this quiz the answer should be $6000.
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COTR Quiz 7.47.5
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Re: COTR Quiz 7.47.5
Originally posted by Courtney View PostWe are still finishing Pre Algebra. For #5 of this quiz the answer should be $6000.
Hmm, it looks like the issue here is rounding. If we round (.085)(2/12) down to .0141 we get the (rounded) answer in the Key: $6028. If we round up to .0142 then we get $5986 (again, rounded). However, if we use a calculator to complete all of the operations in one step, not rounding until the end, then we get an even $6000. Now, that is as far as my math abilities go, so hopefully Cindy will chime in on which answer she would expect from a student.
HTH (at least temporarily)!Michael
Memoria Press

Re: COTR Quiz 7.47.5
Thanks. The question was answered in number 17 of Lesson 7.5. You multiply both sides by 6 instead of multiplying (0.085)(1/6) first. I did the same thing Micheal because of the way it is shown in the quiz key until I looked in the solutions manual.Courtney
Mom to 5 boys14,13,10,8,5 and the girls 3 and 1
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Re: COTR Quiz 7.47.5
Originally posted by Courtney View PostThanks. The question was answered in number 17 of Lesson 7.5. You multiply both sides by 6 instead of multiplying (0.085)(1/6) first. I did the same thing Micheal because of the way it is shown in the quiz key until I looked in the solutions manual.
I don't have the solutions guide at home, but here is my solution to the problem (difficult to type in text format, but hopefully it will make sense).
Equation for simple interest: I = prt
Solve for p: p = I/rt
Convert interest rate to decimal form: 8.5% = .085
Since the interest rate is annual, divide 0.085/12 to get monthly equivalent, r, but don't do the division yet. Leave in integer form.
t = 2months (given)
I = $85 (given)
substituting: p = 85/[(0.085/12)*2]
simplify the denominator: p = 85/(0.085/6)
multiply by reciprocal of the denominator to complete the division: p = 6*85/0.085
simplify: p = 6*1000 = $6,000
Hope this helps! (Sounds like the answer key needs to be corrected.)Cindy Davis
Science and Math teacher at Highlands Latin School  Indianapolis
ds24 college graduate: working, reading, writing
ds23 college graduate: 1st year med school
dd21 college junior: Nursing
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