Question

simple interest on rupees thousand increase by rupees 20 Wendy time increases 2 years find the rate percent per annum​

Answer 1

Answer: R = 1%

Given:

• Principal Amount = Rs. 1000
• SI = x + 20
• Time = y + 2

To Find:

• Rate% = ?

Solution:

The value of SI when the Time is 'y' years is:

$\implies SI = \dfrac{P\times R\times T}{100}\\\\\\\implies SI = \dfrac{ 1000 \times R \times y}{100}\\\\\\\implies \boxed{SI = 10 \times R \times y} \hspace{20} ...(i)$

When the Time is 'y+2' years, it is given that the SI is increase by Rs. 20. Hence we get:

$\implies SI + 20 = \dfrac{ 1000 \times R \times (y+2)}{100}\\\\\\\implies SI + 20 = 10 \times R \times (y+2) \hspace{20} ...(ii)$

Substituting the value of SI from (i) in (ii), we get:

$\implies 10Ry + 20 = 10 \times R \times ( y + 2 )\\\\\\\implies 10Ry + 20 = 10Ry + 2 ( 10R )\\\\\\\text{10Ry gets cancelled on both sides. Hence we get,}\\\\\\\implies 20 = 20R\\\\\\\implies \boxed{R = \dfrac{20}{20} = 1\%}$

Hence the Rate of interest per annum is 1%.

Answer 2

Answer:

Answer: R = 1%

Given:

Principal Amount = Rs. 1000

SI = x + 20

Time = y + 2

To Find:

Rate% = ?

Solution:

The value of SI when the Time is 'y' years is:

When the Time is 'y+2' years, it is given that the SI is increase by Rs. 20. Hence we get:

Substituting the value of SI from (i) in (ii), we get:

⟹10Ry+20=10×R×(y+2)⟹10Ry+20=10Ry+2(10R)10Ry gets cancelled on both sides. Hence we get,⟹20=20R⟹R=2020=1%\begin{lgathered}\implies 10Ry + 20 = 10 \times R \times ( y + 2 )\\\\\\\implies 10Ry + 20 = 10Ry + 2 ( 10R )\\\\\\\text{10Ry gets cancelled on both sides. Hence we get,}\\\\\\\implies 20 = 20R\\\\\\\implies \boxed{R = \dfrac{20}{20} = 1\%}\end{lgathered}

⟹10Ry+20=10×R×(y+2)

⟹10Ry+20=10Ry+2(10R)

10Ry gets cancelled on both sides. Hence we get,

⟹20=20R

⟹ R= 20/20

=1%

Hence the Rate of interest per annum is 1%.