How many multiples of 7 lie between 150 and 250?

The correct answer is Option (2) → 14

Find the first and the last multiples of 7 inside the range; the multiples between them go up by 7, so counting them is counting the steps.

• First multiple after 150: \(7\times21=147\) is too small, so it is \(7\times22=154\)

• Last multiple before 250: \(7\times36=252\) is too big, so it is \(7\times35=245\)

• Multiples from \(7\times22\) to \(7\times35\): \(35-22+1=14\)