Question
Mathematics Question on Sum of First n Terms of an AP
The number of 3-digit numbers, that are divisible by either 2 or 3 but not divisible by 7 , is_________
Answer
The correct answer is 514
Divisible by 2→450
Divisible by 3→300
Divisible by 7→128
Divisible by 2 & 7→64
Divisible by 3 & 7→43
Divisible by 2 & 3→150
Divisible by 2,3 & 7→21
∴ Total numbers =450+300−150−64−43+21=514