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Bikash Kumar Giri

· started a discussion

· 1 Months ago

Plz Make correct

Question:
An amount becomes \(\unicode{x20B9} \)3795 in 3 years and \(\unicode{x20B9} \)4537.50 in 7 \(\cfrac{1}{2}\) years on simple interest. Find the rate of interest.
Options:
A) 6% per year
B) 4% per year
C) 4.5% per year
D) 5% per year
Solution:
Ans: (d) Let the principal be P and rate be r%.

From question,


Dividing equ. (ii) by equ. (i), 


Knowledge Expert

· commented

· 1 Months ago

Dear Student,

See the explanation in the way which you want:

Amount = Simple Interest + Principal ______________(1)

Means

A=SI+P

We know,

Simple Interest, SI = (P*R*T)/100

Put SI the value of SI in equation(1):

A=(P*R*T)/100 + P

A = P(1+ RT/100)


An amount becomes ₹3795 in 3 years

So, it can be represented as:

3795 = P(1+ 3R/100)

P=379500 / 3R+100 _____________(2)

Same amount becomes ₹4537.50 in 7.5 years

So, it can be represented as:

4537.50 = P(1+ 7.5R/100)

P=453750 / 7.5R+100 _____________(3)

From (2) and (3),

379500 / 3R+100 = 453750 / 7.5R+100

Now, you must know how to calculate the value of R from the above equation.

R = 5%

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Knowledge Expert

· commented

· 1 Months ago

Its SI.....not CI....

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