Find the sum of all positive multiples of 3 less than 50 :
A. 400
B. 404
C. 408
D. 412
Answer: Option C
Solution (By Examveda Team)
First multiple = 3Last multiple (less than 50) = 48
Number of multiples of 3
= $$\frac{48 - 3}{3}$$ + 1
= 16
Sum :
= $$\frac{16}{2}$$ [2 × 3 + (16 - 1)3]
= 8 × 51
= 408

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