simple interest and compound interest tricks - Wikitechy https://www.wikitechy.com/interview-questions/tag/simple-interest-and-compound-interest-tricks/ Interview Questions Mon, 20 Sep 2021 10:22:31 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png simple interest and compound interest tricks - Wikitechy https://www.wikitechy.com/interview-questions/tag/simple-interest-and-compound-interest-tricks/ 32 32 The simple interest earned on a certain amount is double the amount when invested for 10 years. What is the interest rate being offered ? https://www.wikitechy.com/interview-questions/simple-interest/the-simple-interest-earned-on-a-certain-amount-is-double-the-amount-when-invested-for-10-years-what-is-the-interest-rate-being-offered/ https://www.wikitechy.com/interview-questions/simple-interest/the-simple-interest-earned-on-a-certain-amount-is-double-the-amount-when-invested-for-10-years-what-is-the-interest-rate-being-offered/#respond Wed, 18 Aug 2021 02:29:23 +0000 https://www.wikitechy.com/interview-questions/?p=2064

The simple interest earned on a certain amount is double the amount when invested for 10 years. What is the interest rate being offered ?

A. 40%

B. 20%

C. 15%

D. 12%

Answer : B. 20%

Explanation:

Interest Earned = 2 Times
Invested year = 10
Interest rate = 2 * 10 = 20

]]> https://www.wikitechy.com/interview-questions/simple-interest/the-simple-interest-earned-on-a-certain-amount-is-double-the-amount-when-invested-for-10-years-what-is-the-interest-rate-being-offered/feed/ 0 A certain sum of money amounts to Rs.1300 in 2 years and to Rs. 1525 in 3.5 years. Find the sum and the rate of interest ? https://www.wikitechy.com/interview-questions/simple-interest/a-certain-sum-of-money-amounts-to-rs-1300-in-2-years-and-to-rs-1525-in-3-5-years-find-the-sum-and-the-rate-of-interest/ https://www.wikitechy.com/interview-questions/simple-interest/a-certain-sum-of-money-amounts-to-rs-1300-in-2-years-and-to-rs-1525-in-3-5-years-find-the-sum-and-the-rate-of-interest/#respond Wed, 18 Aug 2021 02:26:10 +0000 https://www.wikitechy.com/interview-questions/?p=2062

A certain sum of money amounts to Rs.1300 in 2 years and to Rs. 1525 in 3.5 years. Find the sum and the rate of interest ?

A. Rs 850 , 10%

B. Rs 900, 12%

C. Rs 800, 13%

D. Rs 1000,15%

Answer : D. Rs 1000, 15%…

Explanation :

1525 – 1300 = 225 for 1.5 yrs (3.5 – 2)
So for one yr 225 / 1.5 = 150
then for 2 yrs interest is 150 + 150 = 300
Then principal 1300 – 300 = 1000.
Now 150 / 1000 * 100 = 15%

]]> https://www.wikitechy.com/interview-questions/simple-interest/a-certain-sum-of-money-amounts-to-rs-1300-in-2-years-and-to-rs-1525-in-3-5-years-find-the-sum-and-the-rate-of-interest/feed/ 0 Vijay invested Rs.50,000 partly at 10% and partly at 15%. His total income after a year was Rs.7000. How much did he invest at the rate of 10% ? https://www.wikitechy.com/interview-questions/compound-interest/vijay-invested-rs-50000-partly-at-10-and-partly-at-15-his-total-income-after-a-year-was-rs-7000-how-much-did-he-invest-at-the-rate-of-10/ https://www.wikitechy.com/interview-questions/compound-interest/vijay-invested-rs-50000-partly-at-10-and-partly-at-15-his-total-income-after-a-year-was-rs-7000-how-much-did-he-invest-at-the-rate-of-10/#respond Tue, 17 Aug 2021 14:59:21 +0000 https://www.wikitechy.com/interview-questions/?p=1788

Vijay invested Rs.50,000 partly at 10% and partly at 15%. His total income after a year was Rs.7000. How much did he invest at the rate of 10% ?

A. 40,000

B. 41,000

C. 12,000

D. 20,000

Answer : A. 40,000…

Explanation :

Let the amount Vijay invested at the rate of 10% = Rs x
The amount invested at 15% = Rs (50,000 – x)
Time = 1yr
Income from 10% rate = 10% of x = x/10
Income from 15% rate = 15% of (50,000 – x) = (150,000 – 3x)/20

According to question,
[x/10] + [(150,000 – 3x)/20] = 7000
150000 – x = 140000
x = 10,000.
Therefore, he has invested Rs 10,000 at 10% and Rs 40,000 at 15%.

]]> https://www.wikitechy.com/interview-questions/compound-interest/vijay-invested-rs-50000-partly-at-10-and-partly-at-15-his-total-income-after-a-year-was-rs-7000-how-much-did-he-invest-at-the-rate-of-10/feed/ 0 Rs.5887 is divided between Shyam and Ram, such that Shyam’s share at the end of 9 years is equal to Ram’s share at the end of 11 years, compounded annually at the rate of 5%. Find the share of Shyam ? https://www.wikitechy.com/interview-questions/compound-interest/rs-5887-is-divided-between-shyam-and-ram-such-that-shyams-share-at-the-end-of-9-years-is-equal-to-rams-share-at-the-end-of-11-years-compounded-annually-at-the-rate-of-5-find-the-s/ https://www.wikitechy.com/interview-questions/compound-interest/rs-5887-is-divided-between-shyam-and-ram-such-that-shyams-share-at-the-end-of-9-years-is-equal-to-rams-share-at-the-end-of-11-years-compounded-annually-at-the-rate-of-5-find-the-s/#respond Tue, 17 Aug 2021 14:57:11 +0000 https://www.wikitechy.com/interview-questions/?p=1787

Rs.5887 is divided between Shyam and Ram, such that Shyam’s share at the end of 9 years is equal to Ram’s share at the end of 11 years, compounded annually at the rate of 5%. Find the share of Shyam ?

A. 2088

B. 2000

C. 3087

D. None of these

Answer : C. 3087…

Explanation :

Shyam’s share * (1 + 0.05)9 = Ram’s share * (1 + 0.05)11
Shyam’s share / Ram’s share = (1 + 0.05)11 / (1 + 0.05)9
= (1 + 0.05)2
= 441/400
Therefore Shyam’s share = (441/841) * 5887
= 3087 .

]]> https://www.wikitechy.com/interview-questions/compound-interest/rs-5887-is-divided-between-shyam-and-ram-such-that-shyams-share-at-the-end-of-9-years-is-equal-to-rams-share-at-the-end-of-11-years-compounded-annually-at-the-rate-of-5-find-the-s/feed/ 0 A sum of money place at compound interest doubles itself in 4 years. In how many years will it amount to eight times itself ? https://www.wikitechy.com/interview-questions/compound-interest/a-sum-of-money-place-at-compound-interest-doubles-itself-in-4-years-in-how-many-years-will-it-amount-to-eight-times-itself/ https://www.wikitechy.com/interview-questions/compound-interest/a-sum-of-money-place-at-compound-interest-doubles-itself-in-4-years-in-how-many-years-will-it-amount-to-eight-times-itself/#respond Tue, 17 Aug 2021 14:36:54 +0000 https://www.wikitechy.com/interview-questions/?p=1782

A sum of money place at compound interest doubles itself in 4 years. In how many years will it amount to eight times itself ?

A. 16

B. 8

C. 12

D. 20

Answer : C. 12…

Explanation :

Let, Principal = Rs. 100.
Amount = Rs. 200.
Rate = r%
Time = 4 years.

Now,
A = P * [ 1 + (r/100) ]n
200 = 100 * [ 1 + (r/100) ]4
2 = [1 + (r/100)]4 ……….. (i)
If sum become 8 times in the time n years, then,
8 = ( 1 + (r/100) )n
23 = ( 1 + (r/100) )n …….. (ii)

Using eqn (i) in (ii), we get
( [1 + (r/100) ]4)3 = ( 1 + (r/100) )n
[1 + (r/100)]12 = (1 + (r/100))n
n = 12 years.

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