QUESTION 5
Easy
Sarita is reading a book of 500 pages. She reads 20 pages everyday. How many pages will be left after 15 days? Express this as a linear pattern.
SOLUTION
1
Identify total pages and daily reading
Total pages in the book \(= 500\)
Pages read per day \(= 20\)
Pages read per day \(= 20\)
2
Find pages read after \(15\) days
Pages read after \(15\) days \(= 20 × 15 = 300\) pages
3
Find pages left
\(\begin{aligned}
\text{Pages left} &= \text{Total pages} − \text{Pages read} \\ &= 500 − 300 \\ &= 200 \text{ pages} \end{aligned}\)
4
Express as a linear pattern
Let number of days be \(n\)
Pages read after \(n\) days \(= 20n\)
Pages left after \(n\) days \(= 500 − 20n\)
This is a linear expression(constant decrease).
Pages read after \(n\) days \(= 20n\)
Pages left after \(n\) days \(= 500 − 20n\)
This is a linear expression(constant decrease).
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Final Answer :
\(200\) pages will be left after \(15\) days
Linear Expression: \(500 − 20n\)
Concept Note
If total pages \(= T\), pages read per day \(= r\),
After \(n\) days:
Remaining pages \(= T − r × n\)