SOLUTION: 2. An investment of $5500 is made at an annual simple interest rate of 4.9%. How much additional money must be invested at an annual simple interest rate of 7.4% so that the total

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Question 262885: 2. An investment of $5500 is made at an annual simple interest rate of 4.9%. How much additional money must be invested at an annual simple interest rate of 7.4% so that the total interest earned is 6.4% of the total investment?

Found 3 solutions by pinklipgloss2007, stanbon, richwmiller:
Answer by pinklipgloss2007(6)   (Show Source):
You can put this solution on YOUR website!
To answer your 4th question:
Use the equation is/of = %/100% (This is very informal, of course).
We don't know what the price of the shoes IS, so we can insert x in place of is. We know the shoes are 55.99, so insert that in place of of. And the 30% goes in place of %, but in decimal form. (0.30). It should look like this:

In order to find x, multiply 0.30 by 55.99 and divide by 100.
Your answer should be 0.16797. Now we add the 2 decimal places that we took away (in the 30%). We should get 16.797. This is the amount of money you save. So add 16.797 to 55.99 and the price of the shoes was 72.79!

Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website!
1.Find three consecutive integers such that the sum of one-half of the smallest and one-third of the largest is one less than the other integer.
1st: x
2nd: x+1
3rd: x+2
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Equation:
(1/2)x + (1/3)(x+2) = (x+1)-1
Multiply thru by 6 to get:
3x + 2(x+2) = 6(x+1) - 6
5x + 4 = 6x
x = 4 (1st)
x+1 = 5 (2nd)
x+2 = 6 (3rd)
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2. An investment of $5500 is made at an annual simple interest rate of 4.9%. How much additional money must be invested at an annual simple interest rate of 7.4% so that the total interest earned is 6.4% of the total investment?
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Equation:
Let the additional amount of money be "x" dollars.
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0.074x = 0.064(x+5500)
Multiply thru by 1000 to get:
74x = 64x + 64*5500
10x = 64*5500
x = 64*550
x = $35,200
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3. How long will it take $2475 to triple at 10.25% simple interest?
A(t) = P(1+rt)
If P = 2475 and p = 0.1025
Equation:
3*2475 = 2475(1+ 0.1025*t)
3 = 1 + 0.1025t
0.1025t = 2
t = 19.51 years
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4. Tim bought a pair of shoes at a 30% discount sale for $55.99. What was the original price of the shoes?
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Let original price be "x".
Equation:
0.70x = 55.99
x = 55.99/0.70
x = $79.99
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Cheers,
Stan H.

Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website!
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Now to problem #2
5500*.049=269.50
5500 dollars yields $269.50
269.50+x*.074=(5500+x)*.064
x=$8250 must be invested at 7.4% so that the total 8250+5500 yields 6.4%
(8250+5500)*.064=880
.074*8250=610.50
$8250 yields $610.50 at 7.4%
269.50+610.50=880
$8250 must be invested at 7.4%