Zoho Simple and Compound Interest Quiz 1

Sol: Given SI = 96000

P = 24000

N = 5

SI =\frac{PNR}{100}

96000 = \frac{24000\times5\timesR}{100}

9600 = 24 x 5 x R

R = 80

Sol: 38200P = P\left ( 1 + \frac{3r}{100} \right ) ………(1)

58400P = P\left ( 1 + \frac{8r}{100} \right ) …………(2)

Subtracting (1) from (2)

58400P - 38200P = P\left ( 1 + \frac{8r}{100} \right ) - P\left ( 1 + \frac{3r}{100} \right )

20200 = \frac{5r}{100}

r = 404000

Sol: Let Parineeti lent Priyanka y Rs at 15% p.a and Nick (80000 - y ) at 20% p.a for 2 years

100,000 = 80,000+\frac{30}{100} \times y + \frac{40}{100}( 80,000 - y )

20,000 = 32000-\frac{1}{10} \times y

\frac{1}{10} \times y = 12,000

y = 1,20,000

Sol: 4851 = P\left ( \frac{r}{100} \right )^{2}

 

4851 = P\left ( \frac{21}{100} \right )^{2}

P = 110000 Rs

Sol: 13p = p + \frac{4pr}{100}

12p = \frac{4pr}{100}

r = 300%

If the rate of interest is increased by 200 percentage points the new rate becomes = 300 + 200 = 500 %

6p = p + \frac{500pn}{100}

5p = 5pn

n = 1 year

Sol: A = 23000 \left ( 1+\frac{20}{100} \right )^{3}

A = 23000 \left ( \frac{120}{100} \right )^{3}

A = 23000\left ( \frac{6}{5} \right )^{3}

A = 23000\left ( \frac{216}{125} \right )

= 39744

C.I = A - P

= 39744 - 23000

= 16744

Sol: As C.I for the 1st year = S.I

Interest for 1st year = 83000*\frac{10}{100}

= 8300 Rs

As interest on interest is C.I

Interest for the 2nd year = 8300 + 8300*\frac{10}{100}

= 8300 + 830 = 9130

Interest for the 3rd year = 9130 + 9130\frac{10}{100}

= 9130 + 913 = 10043

Total interest at the end of 3 years = 8300 + 9130 + 10043

= 27473

Therefore t = 3

Sol: Using interest on interest is C.I

17350 + 173.5r = 18391

173.5r = 1041

r = 6

Sol:  P ….. In 17 years…….3P

As amount at the end will become principal for next year

3P …….in 17 years……9P

9P …….in 17 years……27P

27P …….in 17 years……81P

81P …….in 17 years……243P

It becomes 81 times itself in 85 years

Sol: 82000( 1 + \frac{10}{100}) = 90200

Let us assume he repaid y Rs at the end of 1st year

( 90200 - y ) ( 1 + \frac{10}{100}) = 31900

90200 - y = 29000

y = 61200