Question

4.
In a city, the Covid cases increase 10% in the month of April, decrease by 10% in the
of May and again decrease by 10% in the month of June. Find the number of Covid sas
registered at the end of June if the cases registered initially were 20000.​

Answer 1

☯GIVEN :

• Covid cases registered initially were 20000.
• Increases 10% in the month of April.
• Decreases 10% in the month of May.
• Again deceases 10% in the month of June.

☯TO FIND :

• Total number of Covid cases
• number of Covid casesregistered at the end of June.

➲SOLUTION :

✞ In April :

⦿ To find total number of Covid Cases in April : We have to add Initially registered cases and 10 % of it.

$\longrightarrow{\sf{20000 + 10\% \: of \: 20000}}$

$\longrightarrow{\sf{20000 + 2000 \cancel{0} \times \dfrac{1 \cancel{0}}{1 \cancel{0}\cancel{0}} }}$

$\longrightarrow{\sf{20000 +2000}}$

$\longrightarrow \underline{\bf{22000}}$

✞ In May :

⦿To find total number of Covid Cases in May : We have to subtract 10% of total covid cases in April from total number of cases in April.

$\longrightarrow {\sf{22000 - 10\% \: of \: 22000}}$

$\longrightarrow {\sf{22000 - 2200\cancel{0} \times \dfrac{1 \cancel{0}}{1\cancel{0}\cancel{0}} }}$

$\longrightarrow{ \sf{22000 - 2200}}$

$\longrightarrow{ \underline{ \bf{19800}}}$

✞ In June :

⦿To find total number of Covid Cases in June : We have to subtract 10% of total number of covid cases in May from total number of cases in May.

$\longrightarrow {\sf{19800 - 10\% \: of \: 19800}}$

$\longrightarrow {\sf{19800 - 1980\cancel{0} \times \frac{1\cancel{0}}{1 \cancel{0}\cancel{0}} }}$

$\longrightarrow \sf{19800 - 1980}$

$\longrightarrow \huge{ \underline { \boxed{\red{\bf{17820}}}}}$

$\huge{\pink{\therefore}}$ Total number of Covid cases registered at the end of June is 17820.