Homework: Section 2.2 (Copy) Score: 0 of 1 pt x 2.2.112 4 18 of 20 (19 complete)
ID: 3137103 • Letter: H
Question
Homework: Section 2.2 (Copy) Score: 0 of 1 pt x 2.2.112 4 18 of 20 (19 complete) HW Score: 425%, 85 of 20 other wants to invest sa oo osor her son's hare educaton. She invests a portion of te noney n a bank centcate of depost CD acount) which earns 4% and the re nande i, a sa ngs bord hat ewns 7% "the interest eaned after one year is $480.00, how much money was ivested in the CD accoun? The tptal interest earned after one year is $480.00 How much money was invested in the CD account? s (Round to the nearest cent, if necessaryExplanation / Answer
If half earned 4% and if half earned 7%, then:
$4000 x 4% = $4000 x 4 / 100 =$160
$4000 x 7% = $4000 x 7 / 100 =$280
$280 + $160 = $440 (Which is $40 short)
If $3500 at 4% and $4500 at 7% was the split, then:
$3500 x 4% = $140
$4500 x 7% = $315
$140 + $315 = 455 (Which is $25 short)
If $3000 at 4% and $5000 at 7% was the split, then:
$3000 x 4% = $120
$5000 x 7% = $350
$120 + $350 = $470 (Which is $10 short)
If $2500 at 4% and $5500 at 7% was the split, then:
$2500 x 4% = $100
$5500 x 7% = $385
$100 + $385 = $485 (Which is $5 too much)
Notice that a pattern has been established. Each swing of $500 has made a difference of $15.
So, to decide how much was invested in each investment, this can divide 500 by 15, then multiply by 5, and then apply the difference to the above equations.
(Or, I could have multiplied by 10 and applied the difference to the equationss where I was $10 short, etc.).
(500 / 15) * 5 = N
500 / 15 = 33.33…
33.33… * 5 = $166.67
$5500 - $166.67 = $5333.33
$2500 + $166.67 = $2666.67
If $2666.67 was invested at 4%, and $5333.33 was invested at 7%, then:
$2666.67 x 4% = $2666.67 x 4 /100 =$106.67 (CD)
$5333.33 x 7% = $5333.33 x 7 /100 =$373.33 (Savings Bond)
Check:
$106.67 + $373.33 = $480
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