Question

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

Answer 1

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, "%",

Complete step-by-step answer:
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.