Question 1 - Page 55 - Least, but not Last! - Chapter 3 Class 7 - Finding Common Ground (Ganita Prakash II)

Transcript

Question 1 - Page 55 A sweet shop gives out free gajak to school children on Mondays. Today is a Monday and Kabamai enjoyed eating the gajak. But she visits the sweet shop once every 10 days. When is the next time she would be able to get free gajak from Sweet shop? (Answer in number of days.)Given that The sweet shop gives free gajak every Monday (which is every 7 days) Kabamai goes to the shop every 10 days We need to find next time she would be able to get a free Gajak This will happen on days which are common multiples of 7 & 10 Finding Common Multiples of 7 & 10 Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, … Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, … We notice that they match first time at 70 Thus, Kabamai will get free gajak again in 70 days Here, 70 is also the Least Common Multiple (LCM) of 7 & 10