BLANKS [1 Marks Each]

Question 11 Mark

$\text{R}=\frac{100\times\text{S.I.}}{(.......)\times\text{T}}$

Answer

$\text{R}=\frac{100\times\text{S.I.}}{(\text{P})\times\text{T}}$

Question 21 Mark

$\text{P}=\frac{100\times(......)}{\text{R}\times\text{T}}$

Answer

$\text{P}=\frac{100\times\text{S.I.}}{\text{R}\times\text{T}}$

Question 31 Mark

AT simple interest a sum becomes $\frac65$ of itself in $2\frac12\text{ years.}$ The rate of interest is (......)% per annum.

Answer

AT simple interest a sum becomes $\frac65$ of itself in $2\frac12\text{ years.}$ The rate of interest is 8% per annum.

Solution:

Let the sum be Rs. x

Amount $=\text{Rs. }\frac65\text{x}$

$\text{S.I.}=\text{A}-\text{P}$

$=\frac{6}{5}\text{x}-\text{x}$

$=\text{Rs. }\frac{\text{x}}{5}$

Let the rate of interest be R %

Time = 2.5 years

$\text{S.I.}=\frac{\text{P}\times\text{R}\times\text{T}}{100}$

$\Rightarrow\frac{\text{x}}{5}=\frac{\text{x}\times\text{R}\times\text{2.5}}{100}$

$\Rightarrow\text{R}=\frac{100}{2.5\times5}$

$\Rightarrow8$

Question 41 Mark

AT (....)% per annum simple interest a sum doubles itself in 10 years.

Answer

AT 10% per annum simple interest a sum doubles itself in 10 years.

Solution:

Let the amount be Rs. x

Amount = Rs. 2x

S.I. = A - P

= 2x - x

= Rs. x

Let the rate of interest be R %

Time = 10 years

$\text{S.I.}=\frac{\text{P}\times\text{R}\times\text{T}}{100}$

$\Rightarrow\text{x}=\frac{\text{x}\times\text{R}\times\text{T}}{100}$

$\Rightarrow\text{R}=\frac{100}{10}$

$\Rightarrow\text{R}=10\%$

MATHS BLANKS [1 Marks Each]