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Question 74544: Can u solve this one plz...
1)A sum of money put out at compound interest increased by $600 at the end of the 1st year and $660 at the end of the 2nd year.Find the rate percent and the sum..
Found 3 solutions by venugopalramana, ikleyn, MathTherapy:
Answer by venugopalramana(3286)   (Show Source):
You can put this solution on YOUR website! Can u solve this one plz...
1)A sum of money put out at compound interest increased by??[IS THIS BY OR TO??] $600 at the end of the 1st year and $660..[THIS ALSO??] at the end of the 2nd year.Find the rate percent and the sum..
IF SUM INCREASED BY 600 IN THE I YEAR IT CAN NOT INCREASE BY ONLY 660.IT HAS TO INCREASE BY AT LEAST >600+600..SO PLEASE CHECK UP.
IF IT IS INCREASED TO THEN WE GET
LET THE SUM =P
RATE % =R
IN 1 YEAR P WILL INCREASE TO
P(1+R/100)=600.......................1
IN 2 YEARS P WILL INCREASE TO
P(1+R/100)^2=660..........................2
EQN.2/EQN.1 GIVES
1+R/100=660/600=1.1
R/100=1.1-1=0.1
R=100*0.1=10
PUTTING IN EQN.1
P*1.1=600
P=600/1.1=545.45
Answer by ikleyn(54062)  (Show Source):
You can put this solution on YOUR website! .
Can u solve this one plz...
1) A sum of money put out at compound interest increased by $600 at the end of the 1st year
and $660 at the end of the 2nd year. Find the rate percent and the sum.
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In his post, tutor @venugopalramana interpreted the problem incorrectly and solved it incorrectly.
See my correct solution below.
Let 'P' be the principal (initial deposit value).
Let 'x' be the annual rate as a decimal.
Then we have these two equations
Px = 600, (1) (first-year increase)
P(1+x)^2 - P(1+x) = 660. (2) (second-year increase)
In the second equation, open parentheses
(P + 2Px + Px^2) - (P + Px) = 600.
Simplify by combining like terms
Px + Px^2 = 660.
Write in this form
Px + (Px)*x = 660.
Replace Px with 600 at each appearance, based on equation (1)
600 + 600x = 660.
Simplify and find x
600x = 660 - 600,
600x = 60,
x = 60/600 = 0.1.
At this point, the problem is solved completely.
ANSWER. The annual rate of compounding is 0.1, or 10%.
Solved.
Answer by MathTherapy(10898)  (Show Source):
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