the portion earning a 5% return

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the portion earning a 5% return

by sanju09 » Thu Sep 16, 2010 10:47 pm
A portion of $6600 is invested at a 5% annual return, while the remainder is invested at a 3% annual return. If the annual income from the portion earning a 5% return is twice that of the other portion, what is the total income from the two investments after one year?
(A) $180
(B) $270
(C) $300
(D) $320
(E) $360


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by goyalsau » Thu Sep 16, 2010 11:13 pm
IS it B 270

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by klmehta03 » Sun Sep 19, 2010 5:06 pm
investment for 5% return= x
investment for 3% return= 6600-x
yeild from 5% reutrn = 0.05x
yield from 3% return= 0.03(6600-x)
0.05x= 2* 0.03 (6600-x)
x=3600
yeild from 5% reutrn = 0.05x= 180
yield from 3% return= 0.03(6600-x)=90
total return 270
ans B

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by tpr-becky » Sun Sep 19, 2010 8:32 pm
Let's let x be the amount invested at 5% the stem gives us the equation

5/100(x)=2(3/100)(6600-x)=
x/20=3/50(6600-x)
x=3(20)/50(6600-x)
x=6/5(6600)-6/5(x)
11/5x=6(1320)
x=3600

so to get the total income we have to calculate 3600 at 5% and 3000 at 3%

3600(5/100)= 36(5)= 180

3000(3/100)=30(3)= 90

180 + 90=270.
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by kaushiksin » Mon Sep 20, 2010 2:07 am
0.05x = 2*0.03(6600-x)
0.05x = 396-0.06x
x = 3600

Answer = 3600*0.05+(6600-3600)*0.03=270