Question

20. A sum of money at a simple rate of interest i
doubles in 5years. At another simple rate of
interest i,, it becomes three times in 12 years.
Then the two rates of interest i, and in
respectively are
2.
2
(a) 10%, 16-%
(b) 10%, 20%
در
(c) 20%, 16-%
(d) 20%, 30%​

Answer 1

Answer:

(c) 20%,16%

Step-by-step explanation:

first condition

P+SI=2P

so

P+(p*r*5)/100=2P

p+(pr/20)=2p

20p+pr=40p

pr=40p-20p

pr=20p

r=20%

Second condition

p+SI=3p

p+(p*r*12)/100=3p

p+3pr/25=3p

25p+3pr=75p

3pr=75p-25p

3pr=50p

r=50/3=16.6%

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