How many natural numbers up to 2001 are divisible by 3,4 but not by 5?
a) 768
b) 801
c) 934
d) 1067
Sol:
Divisible by 3 till 2001 = 667
Divisible by 4 till 2001 = 500
Divisible by 12 till 2001 = 166 ⇒ Divisible by 3, 4 = 667 + 500 – 166 = 1001
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