# Aptitude - Compound Interest - Discussion

Discussion Forum : Compound Interest - General Questions (Q.No. 7)

7.

At what rate of compound interest per annum will a sum of Rs. 1200 become Rs. 1348.32 in 2 years?

Answer: Option

Explanation:

Let the rate be R% p.a.

Then, 1200 x | 1 + | R | 2 | = 1348.32 | ||

100 |

1 + | R | 2 | = | 134832 | = | 11236 | |||

100 | 120000 | 10000 |

1 + | R | 2 | = | 106 | 2 | |||||

100 | 100 |

1 + | R | = | 106 |

100 | 100 |

R = 6%

Discussion:

40 comments Page 1 of 4.
Daba said:
2 years ago

Very good, Thanks all for explaining.

(1)

Etsub said:
2 years ago

I can't understand it. Please explain me to get it.

Chimi said:
3 years ago

When 134832/12 = 11236.

120000/12 = 10000.

120000/12 = 10000.

(3)

Kaushal said:
4 years ago

How to do this problem without applying formula?

(1)

Sanjeev said:
4 years ago

@Praveen.

It's logically.

It's logically.

Vaibhav said:
5 years ago

How come 11236?

Saikat Ghosh said:
6 years ago

@Linka.

The shortcut method to find the Square root of 11236 is:

1*1=1,

2*2=4,

3*3=9,

4*4=16,

5*5=25, 6*6=36, 7*7=49, 8*8=64, 9*9=64, 10*10=100, 11*11=121, 12*12=144..

At first, see the last no i.e 6.

So 6 can be found either in 4 square or in 6 square.

Now, look at the first three numbers i.e. 112 which is near to square 10 as the square root of 11 will be more.

So 10*(10+1)=110.

Now see that 112<110.

So 6 square will be taken. Therefore square root of 11236 is 106.

The shortcut method to find the Square root of 11236 is:

1*1=1,

2*2=4,

3*3=9,

4*4=16,

5*5=25, 6*6=36, 7*7=49, 8*8=64, 9*9=64, 10*10=100, 11*11=121, 12*12=144..

At first, see the last no i.e 6.

So 6 can be found either in 4 square or in 6 square.

Now, look at the first three numbers i.e. 112 which is near to square 10 as the square root of 11 will be more.

So 10*(10+1)=110.

Now see that 112<110.

So 6 square will be taken. Therefore square root of 11236 is 106.

(1)

Suraj said:
6 years ago

What is the answer, if 9 months is given here instead of 2 years?

Aarav said:
6 years ago

Give shortcut to get the answer clearly.

Praveena said:
6 years ago

1+R/100=106/100.

R/100=106/100-1,

R/100=106-100/100,

R/100=6/100,

100R=600,

R=6.

R/100=106/100-1,

R/100=106-100/100,

R/100=6/100,

100R=600,

R=6.

(5)

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