Question

Qn.4. At what rate per cent will a sum
of Rs. 3,125 amount to Rs 3,645 in two
years?
O 10%
O 6%
O 8%
12%​

Answer 1

Answer :-

･ Rate of interest is 8.32% or 8%

Option c.) is correct answer.

Given :-

✧ Principal (P) = Rs. 3125

✧ Time (T) = 2 years

✧ Amount (A) = Rs. 3645

To find :-

◍ Rate of interest (R)

Formula used :-

$\mapsto \tt{Simple\:\: Interest = \dfrac{Principal \times Rate \: \: of \: \: interest \times Time}{100} } \\ \\ \mapsto \tt{Simple \: \: Interest (S.I.) = Amount - Principal}$

Solution :-

Firstly find Simple interest,

S.I. = Amount - Principal

S.I. = Rs. 3645 - Rs. 3125

S.I. = Rs. 520

Now, we will substitute the values of P, T and S.I. in simple interest formula. By this we will get rate of interest.

$\longrightarrow\tt{S.I. = \dfrac{PRT}{100} } \\ \\ \longrightarrow\tt{ \dfrac{S.I. \times 100}{PT} =R}\\ \\ \longrightarrow\tt{R = \dfrac{520 \times 100}{3125\times 2}}\\ \\ \longrightarrow\tt{R = \dfrac{52000}{6250}}\\ \\ \longrightarrow\tt{R=8.32 \: \: or \: \: 8}$

Rate of interest (R) = 8.32% or 8%

More Information :-

• Amount = Simple interest + Principal

• Simple Interest = (Principal × Rate of Interest × Time)/100

• Rate of interest = (Simple interest × 100)/ (Principal × Time)

• Principal = (Simple interest × 100)/ (Rate of interest × Time)

• Time = (Simple interest × 100)/ (Rate of interest × Principal)

Answer 2

Answer:

Question⤵

➡4. At what rate per cent will a sum

of Rs. 3,125 amount to Rs 3,645 in two

years?

O 10%

O 6%

O 8%

12%

Answer⤵

➡Option (C) 8% is correct answer.

Given⤵

➡Principal (P) = Rs. 3125

➡Time (T) = 2years

➡Amount(A) =Rs.3645

To find ⤵

➡Rate of interest (R)

Formula used

➡

$simple \: interest = \frac{principal \times rate \times time}{100} \\ simple \: interest = amount - principal$

Solution⤵

➡Firstly we had to find Simple interest ,

➡S. I. = Amount-Principal

➡S. I. =Rs.3645-Rs.3125

➡S. I. =Rs.520

➡Now we had to substitute the value of P, T, R and S. I. in S. I. formula

➡S. I. = PRT/100

➡R= S. I. ×100/PT

➡R=

$\frac{520 \times 100}{3125 \times 2}$

➡R= 52000/6250

➡R=8.32%

Therefore Rate of interest (R) = 8%.

Some extra formula ⤵

➡Amount= Principal +Simple Interest

➡Simple interest= (Principal×Rate ×Time) /100

➡Time = (Simple Interest×100)/(Principal ×Rate)

Hope this is helpful to you!