A newspaper seller sells (160) newspapers on the first day and (30) more newspapers each next day. On which day will (610) newspapers be sold?
Answer and explanation
Correct answer: 16
This is an AP with first term \(a=160\) and common difference \(d=30\). Sales on the \(n\)th day are \(a_n=160+(n-1)30\). Setting this equal to 610 gives \(160+(n-1)30=610\), so \((n-1)30=450\), \(n-1=15\), and \(n=16\). Therefore, 610 newspapers will be sold on the 16th day. On the 15th day, the sales would be 580, so that close option is incorrect. Exam tip: for a target value in an AP, equate it to \(a_n=a+(n-1)d\).
Frequently asked questions
What is the correct answer to this question?
16
Why is this the correct answer?
This is an AP with first term \(a=160\) and common difference \(d=30\). Sales on the \(n\)th day are \(a_n=160+(n-1)30\). Setting this equal to 610 gives \(160+(n-1)30=610\), so \((n-1)30=450\), \(n-1=15\), and \(n=16\). Therefore, 610 newspapers will be sold on the 16th day. On the 15th day, the sales would be 580, so that close option is incorrect. Exam tip: for a target value in an AP, equate it to \(a_n=a+(n-1)d\).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Word problems based on APs.
