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A certain sum of money doubles itself at simple interest in 8 years. In how many years will it be three times at the same rate

A certain sum of money doubles itself at simple interest in 8 years. In how many years will it be three times at the same rate

Grade:7

3 Answers

Saurabh Koranglekar
askIITians Faculty 10335 Points
4 years ago
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Sayantan Garai
117 Points
4 years ago
Sum of money = p
Interest = r%
Time1 = 8y
Time2 = t
 
Hence, p×r×8/100 = p [As the money doubles, interest accumulated will be same as the amount of money].
=> r=12.5
 
In the second case, p×r×t/100 = 2p [3p = p+2p(interest)]
=> t = 200/r = 16.
 
Hence, required time = 16y.
Yashraj
908 Points
3 years ago

Let the principle be 100.

Then amount will be 200.

Interest= 100

Time = 8 yrs

R=?

I=PRT/100

100=100*R*8/100

100*100/100*8=R

100/8=R

NOW SUM SHOULD BE 4 TIMES MEANS 400

MEANS INTREST ON 100 IS 300.

I=PRT/100

300=100*100/8*T/100

300*8/100=T

24= T

IN 24 YEARS SUM WILL BECOME 4 TIMES OF PRINCIPLE

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