Question

# Find(a) 15% of 250 (b) 1% of 1 hour (c) 20% of Rs 2000.

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Hint: To find the percentage of any value take that value in multiple of percentage and convert the given percentage form in fraction form. A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, "%",

a.Step I: The given value is 250.
Step II: We consider the unknown value as x
Step III: we will take 250 as 100% hence we get, $250 = 100\%$ .
Step IV: in the same way, the unknown value x is 15% then we get, x = 15% .
Step V: so we have two equations,
250 = 100% ………………….(i)
x = 15% ………………………(ii)
Step IV: dividing the equation (i) by the equation (ii) then we get,
$\dfrac{{250}}{x} = \dfrac{{100\% }}{{15\% }}\\ \dfrac{{250}}{x} = \dfrac{{100}}{{15}}\\ 250 \times 15 = 100 \times x$
On simplifying the equation we get,
$x = \dfrac{{250 \times 15}}{{100}}\\ x = \dfrac{{3750}}{{100}}\\ x = 37.5$
Hence the $15\%$ of 250 is 37.5
So, the correct answer is “37.5”.

b.Step I: The given value is 1 hour.
Step II: We consider the unknown value as x
Step III: we will take 1 hour as $100\%$ hence we get, $1\;{\rm{hour}} = 60\;{\rm{minutes = }}100\%$ .
Step IV: In the same way, the unknown value x is $1\%$ then we get, $x = 1\%$ .
Step V: so we have two equations,
$60\;{\rm{minutes}} = 100\%$ ………………….(i)
$x = 1\%$ ………………………(ii)
Step IV: dividing the equation (i) by the equation (ii) then we get,
$\dfrac{{60\;{\rm{minutes}}}}{x} = \dfrac{{100\% }}{{1\% }}\\ \dfrac{{60\;{\rm{minutes}}}}{x} = \dfrac{{100}}{1}\\ 60\;{\rm{minutes}} \times 1 = 100 \times x$
On simplifying the equation we get,
$x = \dfrac{{60\;{\rm{minutes}} \times 1}}{{100}}\\ x = \dfrac{{60\;{\rm{minutes}}}}{{100}}\\ x = 0.6\;{\rm{minutes}}$
Hence the $1\%$ of 1 hour is $0.6\;{\rm{minutes}}$ .
So, the correct answer is “ $0.6\;{\rm{minutes}}$ ”.

c.Step I: The given value is Rs 2000.
Step II: We consider the unknown value as x
Step III: we will take Rs 2000 as $100\%$ hence we get, ${\rm{Rs }}2000 = 100\%$ .
Step IV: In the same way, the unknown value x is $20\%$ then we get, $x = 20\%$ .
Step V: so we have two equations,
${\rm{Rs }}2000 = 100\%$ ………………….(i)
$x = 20\%$ ………………………(ii)
Step IV: dividing the equation (i) by the equation (ii) then we get,
$\dfrac{{{\rm{Rs }}2000}}{x} = \dfrac{{100\% }}{{20\% }}\\ \dfrac{{{\rm{Rs }}2000}}{x} = \dfrac{{100}}{{20}}\\ {\rm{Rs }}2000 \times 20 = 100 \times x$
On simplifying the equation we get,
$x = \dfrac{{{\rm{Rs }}2000 \times 20}}{{100}}\\ x = \dfrac{{40000}}{{100}}\\ x = 400$
Hence the $20\%$ of Rs 2000 is 400
So, the correct answer is “ 400”.

Note: Always convert the value of percentage in fraction form by removing the percentage symbol and taking 100 in denominator of the given value. A percentage is a dimensionless number; it has no unit of measurement.