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Per NCERT, the sum of 2-digit numbers DIVISIBLE BY 3 (12, 15, 18, ..., 99) is which value?
A999
B1750
C1665 (an AP with a=12, d=3, l=99 → n = 30; sum = 30/2 × (12+99) = 15 × 111 = 1665)
D1500
Answer & Solution
Correct answer: C. 1665 (an AP with a=12, d=3, l=99 → n = 30; sum = 30/2 × (12+99) = 15 × 111 = 1665)
Per NCERT Exercise 8.2.5, 2-digit multiples of 3 form AP: 12, 15, ..., 99. n = 30. Sum = n/2 × (a + l) = 15 × 111 = 1665.
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