Question

Deepika went to school for 187 days in a full year. If her attendance is 85 %, find the number of
days on which the school was opened.
128 Mathematics-7​

Answer 1

Let the total number of days for which the school was open be x.

Number of days Deepika went to school = 187

Her attendance percentage = 85%

Then :-

Total number of days for which the school was open :-

$= \frac{\texttt{85}}{\texttt{100} }×x \texttt{ \: = 187}$

$= \: x \: =\texttt{ 187 ÷ \: }\frac{\texttt{85}}{\texttt{100}}$

$= x \: = \: \texttt{187 \: × \: } \frac{\texttt{100}}{\texttt{85} }$

$= x = \frac{\texttt{187×100}}{\texttt{85} }$

$= x = \frac{\texttt{18700}}{\texttt{85} }$

$\hookrightarrow \:\color{hotpink} x \texttt{ \: = \: 220}$

Number of days for which the school was open = 220

Let us check whether or not we have found out the correct number of days for which the school was open, by checking if or not 187 constitutes 85% of 220 :-

$= \frac{\texttt{85}}{\texttt{100} }×\texttt{220} \texttt{ \: = 187}$

$= \frac{\texttt{85×220}}{\texttt{100}} \: = \texttt{ \: 187}$

$= \frac{\texttt{18700}}{\texttt{100}} \texttt{ \: = 187}$

$= \texttt{187 = 187}$

Since 187 is constituting 85% of 220, we can conclude that we have found out the correct number of days for which the school was open .

Therefore, the number of days for which Deepika's school was open = 220