If the game is played for the numbers from 1 till 90, find out: a. How many times would the children say 'idli' (including the times they say 'idli-vada')? b. How many times would the children say 'vada' (including the times they say 'idli-vada')? c. How many times would the children say 'idli-vada'?
Children say 'idli' 30 times (all multiples of 3 from 1 to 90).
Children say 'vada' 18 times (all multiples of 5 from 1 to 90).
Children say 'idli-vada' 6 times (common multiples of 3 and 5).
Explanation
(a) The chapter explains that 'idli' is said for multiples of 3. From 1 to 90, there are 90 ÷ 3 = 30 multiples of 3. (b) The chapter explains that 'vada' is said for multiples of 5. From 1 to 90, there are 90 ÷ 5 = 18 multiples of 5. (c) Common multiples of 3 and 5 are multiples of LCM(3,5) = 15. From 1 to 90, there are 90 ÷ 15 = 6 multiples of 15.