Question

Ramesh borrowed Rs 2400 with the condition that he will return Rs 2800 at the end of 2 years. How much
interest does he pay per annum?​

Answer 1

Given -

• Principal (P) = Rs.2400
• Time (T) = 2 years
• Amount (A) = Rs.2800

To find -

• Rate of Interest (R)

Solution -

• As we know that

→ Amount = Principal + Simple Interest

→ 2800 = 2400 + S.I

→ S.I = 2800 - 2400

→ S.I = Rs.400

•°• Simple Interest = Rs.400

• According to the formula of simple Interest

→ S.I = P × R × T/100

→ 400 = 2400 × R × 2/100

→ 400 = 24 × R × 2

→ 400 = 48 × R

→ R = 400/48

→ R = 100/12

→ R = 25/3 %

→ R = 8 ⅓ %

•°• Rate of interest is 8 ⅓ %

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Answer 2

Gɪᴠᴇɴ :

• Ramesh borrowed Rs. 2400 with the condition that he will return Rs 2800 at the end of 2 years.

$:\longrightarrow\:\:\bf{Principal\:amount\:(P)\:=\:Rs.2400\:}$

$:\longrightarrow\:\:\bf{Amount\:repaid\:(A)\:=\:Rs.2800\:}$

$:\longrightarrow\:\:\bf{Time\:(T)\:=\:2\:years\:}$

Tᴏ Fɪɴᴅ :

• Interest that Ramesh pay per annum, i.e. Rate (R).

Sᴏʟᴜᴛɪᴏɴ :

Wᴇ ᴋɴᴏᴡ ᴛʜᴀᴛ,

➣ Simple interest (S.I) is calculated as,

$\pink\bigstar{\underline{\red{\boxed{\bf{\green{S.I\:=\:\dfrac{P\times{R}\times{T}}{100}}}}}}}$

Aɢᴀɪɴ ᴡᴇ ᴋɴᴏᴡ ᴛʜᴀᴛ,

$\red\checkmark\:\:{\underline{\bf{\blue{S.I\:=\:Amount\:(A)\:-\:Principal\:(P)}}}}$

➣ Let us put this value in the above equation, we get

$:\implies\:\:\bf{A\:-\:P\:=\:\dfrac{P\times{R}\times{T}}{100}}$

$:\implies\:\:\bf{2800\:-\:2400\:=\:\dfrac{P\times{R}\times{T}}{100}}$

$:\implies\:\:\bf{R\:=\:\dfrac{400\times{100}}{P\times{T}}}$

$:\implies\:\:\bf{R\:=\:\dfrac{40000}{2400\times{2}}}$

$:\implies\:\:\bf{R\:=\:\dfrac{40000}{4800}}$

$:\implies\:\:\bf{R\:=\:\dfrac{25}{3}}$

$:\implies\:\:\bf\pink{R\:=\:8.34\%}$

$\Large\bf\orange{Therefore,}$

Ramesh pays 8.34 % interest per annum.