Question

6. Find the rate percent per annum when
a principal of 7,000 earns a S.I. of 1,680
in 16 months.
-
​

Answer 1

SOLUTION :-


Given-


Principal ( P ) = Rs. 7000


Simple Interest ( S.I.) = Rs. 1680


Time ( T ) = 16months = 16/12 years = 4/3 years



To Find-



Rate percent per annum??



${\boxed{\boxed{\sf{\red{\:\:\:S.I.=\frac{P \times R \times T}{100}\:\:\: }}}}}$



${\sf{\purple{ 1680=\frac{7000 \times R \times\frac{4}{3} }{100} }}}$



${\implies{\purple{\sf{1680=\frac{7000 \times R \times 4}{100 \times 3}} }}}$



${\implies{\purple{\sf{R=\frac{1680 \times 100 \times 3}{7000 \times 4} }}}}$



${\implies{\purple{\sf{R=6 \times 3}}}}$



${\implies{\underline{\boxed{\pink{\sf{R=18\: percent}}}}}}$

Answer 2

GIVEN :–

• Principal amount = 7,000

• Simple Interest = 1,680

• Time = 16 months = (16/12) year = 4/3 year

TO FIND :–

• Rate = ?

SOLUTION :–

• We know that –

$\\ \implies \large {\boxed{\boxed { \bold{Simple \: \: Interest = { \dfrac{Principal \times Rate(in \: \%) \times Time}{100}}}}}}$

• Put the values –

$\\ \implies { \bold{1680 = { \dfrac{7000 \times Rate(in \: \%) \times \left( \frac{4}{3} \right) }{100}}}}$

$\\ \implies { \bold{ \dfrac{168}{700} \times \dfrac{3}{4} \times 100 = Rate(in \: \%) }}$

$\\ \implies { \bold{ Rate(in \: \%) = \dfrac{168}{700} \times \dfrac{3}{4} \times 100 }}$

$\\ \implies { \bold{ Rate(in \: \%) = \dfrac{504}{2800} \times 100 }}$

$\\ \implies { \bold{ Rate(in \: \%) = \dfrac{504}{28} }}$

$\\ \implies \large{ \boxed { \bold{ Rate= 18 \: \% }}}$

$\\ \rule{220}{2}$