Question

Find the number of number between 100 to 400 which are divisible by either 2 ,3 ,5 and 7

Answer 1

First, there are 150 numbers divisible by 2. Take them away. Of the remaining, every third one is divisible by 3. Take them out and there are 100 left. Every 5th is divisible by 5. 100/5 is 20 so when taken out there are 80 left. Every 7th is divisible by 7, so there remain 6/7 of these: 80*6/7=68.57. Round down to 68.

So we have 300-68=232 that are divisible by 2,3,5,7.

Answer 2

Answer:

232 or 233 are the no.s divisible by either 2,3,5 and 7