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The sum of all two-digit numbers divisible by 5 is:

  • A.1035
  • B.990
  • C.945
  • D.900

Answer: C

The two-digit numbers divisible by 5 are 10, 15, 20, ..., 95. This is an arithmetic progression.

First term (a) = 10. Last term (l) = 95. Common difference (d) = 5.

Number of terms (n) = \((\frac{l-a}{d}) + 1 = (\frac{95-10}{5}) + 1 = 17 + 1 = 18\).

Sum = \(\frac{n}{2}(a+l) = \frac{18}{2}(10+95) = 9 \times 105 = 945\).

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