alleryHow many positive integers less than 1000 are divisible by neither 2 nor 5?
A300
B500
C450
D400
Answer & Solution
Correct answer: D. 400
**From 1 to 999:** divisible by 2
→ 499, by 5 → 199, by 10
→ 99. By inclusion-exclusion, divisible by 2 or 5 $= 499+199-99 = 599$.
Neither $= 999 - 599 = 400$.
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