Question

Rs 4000 gives an interest rs 720 at 9 %. Find time period.​

Answer 1

Gɪᴠᴇɴ:

• $\sf{Principal\:\leadsto\:Rs.\:4000}$
• $\sf{Interest\:\leadsto\:Rs.\:720}$
• $\sf{Rate\:\leadsto\:9\:\%}$

${ }$

Fɪɴᴅ:

• $\sf{Time}$

${ }$

Sᴏʟᴜᴛɪᴏɴ:

$\small\tt{\blue{ᴡᴇ\: ᴋɴᴏᴡ\::}}$

• $\bf{Interest\:\Rightarrow\:{\frac{P\:\times\:R\:\times\:T}{100}}}$

• $\bf{Time\:\Rightarrow\:{\frac{100\:\times\:Interest}{P\:\times\:R}}}$

${ }$

$\bigstar\:\small\tt{\red{ɴᴏᴡ,\: ᴘᴜᴛᴛɪɴɢ\: ᴛʜᴇ\: ᴠᴀʟᴜᴇ\:-}}$

${ }$

$\:\:\:\:\:\:\::\:\Longrightarrow\sf\:{\frac{100\:\times\:720}{4000\:\times\:9}}$

$\:\:\:\:\:\:\::\:\Longrightarrow\sf\:{2\:month}$

${ }$

$\:\:\:\:\:\:\:\:\:\:\therefore\:{\underline{\sf{Hence,\:the\:time\:is\:{\bold{\green{\mathfrak{2\:month}}}}}}}.$

Answer 2

Given :

• Principal (P) = Rs 4000
• Simple Interest (SI) = Rs 720
• Rate (R) = 9%

To Find :

• Time (T)

Solution :

✰ As we know that, Simple Interest is given by SI = P × R × T/100 . So Time will be given by T = SI × 100/P × R where SI, P , R , and T stands for Simple Interest, Principal, Rate and Time respectively. Now let's put the given values in the formula to find the Time Period.

⠀

⟶⠀Simple Interest = P × R × T/100

⟶⠀Time = SI × 100/P × R

⟶⠀Time = 720 × 100/4000 × 9

⟶⠀Time = 720/40 × 9

⟶⠀Time = 72/4 × 9

⟶⠀Time = 72/36

⟶⠀Time = 2 years

⠀

Thus Time Period is 2 years

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★ Additional Info :

$\small\boxed{\begin{array}{cc}\large \color{lime} \boxed{\sf \color{orange}\dag \: \color{aqua}{\underline{More \: Formulae} \: \color{orange}\dag} }\\ \\ \bigstar \: \sf{Principle :- \dfrac{SI \times 100}{R \times T}} \\ \\\bigstar \: \sf{Rate \: of \: Interest :- \dfrac{SI \times 100}{P \times T}} \\ \\ \bigstar \: \sf{Time :- \dfrac{SI \times 100}{P \times R}}\end{array}}$