Question

If the simple interest for 3 years on Rs.10500 is Rs.
1890 then the rate of interest is
Answer:
O 9% p.a.
O 6% p.a.
O 3% p.a.
7% p.a.​

Answer 1

Given:

• Principal = Rs. 10500
• Simple Interest = Rs. 1890
• Time = 3 years

What To Find:

We have to find -

• The rate of interest with the help of the options.

Options:

A. 9 % p.a

B. 6 % p.a

C. 3 % p.a

D. 7 % p.a

Solution:

We know that -

→ SI = [P × R × T] ÷ 100

Where -

• P = Principal
• R = Rate
• T = Time
• SI = Simple Interest

Substitute the values,

→ 1890 = [10500 × R × 3] ÷ 100

Cancel the zeros,

→ 1890 = 105 × R × 3

Multiply the numbers,

→ 1890 = 315 × R

Take 315 to LHS,

→ 1890 ÷ 315 = R

Divide 1890 by 315,

→ 6 = R

Final Answer:

∴ Thus, the rate of interest is 6 % p.a i.e Option B.

Answer 2

$\underline{\underline{\bigstar{\textbf{\textsf{given\::-}}}}}$

• Principle = Rs 10,500
• Rate = ?
• Time = 3
• Simple Interest = Rs 18,90

$\underline{\underline{\bigstar{\textbf{\textsf{\: we \: have \: to \: find \: rate\::-}}}}}$

$\underline{\underline{\bigstar{\textbf{\textsf \purple{{formula \: required \: :-}}}}}}$

$\bold{\bigstar{\underline{\boxed{\sf{ \red{ R = \dfrac{100 \times S. I}{P \times T}}}}}}}$

Where,

• S.I = Simple Interest
• P = Principle
• R = Rate
• T = Time

$\underline{\underline{\bigstar{\textbf{\textsf{\ solution\: :-}}}}}$

$\bold{\purple{Principle} = Rs 10,500} \\ \bold{ \purple{Rate} = \red ? }\\\bold{\purple{Time} = 3} \\\bold{\purple{Simple \: Interest} = Rs 18,90 }$

$\quad{ :\longmapsto{\tt{ R = \dfrac{100 \times S.I }{P \times T}}}}$

★Substitute the values

$\quad{ :\longmapsto{\tt{ R = \dfrac{100 \times 1890 }{10500 \times 3}}}}$

$\quad{ :\longmapsto{\tt{ R = \dfrac{189000 }{31500}}}}$

$\quad{ :\longmapsto{\tt{ R = \cancel\dfrac{189000 }{31500}}}}$

$\quad{ :\longmapsto{\tt{R =6 }}}$

Therefore, the rate is equal to 6%.

$\mathfrak{hence \: the \: correct \: \red{option \: is \: b}}$