How many numbers are there which are divisible by neither 5 nor 7, in the set {200, 201, 202, ....., 798, 799, 800}?
Q. How many numbers are there which are divisible by neither 5 nor 7, in the set {200, 201, 202, ....., 798, 799, 800}?
Answer: 411
Notes: Because total numbers in the given set are : (800 - 200) + 1 = 601.
Since we have calculated number of numbers which are divisible by either 5 or 7 or both in just earlier question : (121 + 86) - 17 = 190.
So the number of numbers which are divisible by neither 5 nor 7 are : 601 - 190 = 411. Therefore option (a) is correct