Maths - LCM and HCF
1. Find the sum of first 5 multiples of4?
- Option : C
- Explanation : First 5 multiples of 4 are as follow . 4 x 1 = 4, 4 x 2 = 8, 4 x 3 = 12, 4 x 4 == 16 and 4x5=20 ∴ Sum of first 5 multiples of 4 = 4 + 8 + 12 + 16 + 20 =60.
2. The number of factors of 540 is -
- Option : D
- Explanation : ∴ 540= 2 x 2 x 5 x 3 x 3 x 3 = 22 x 51 X 33 ∴ Number of factors =(2+ 1)(1+ 1)(3+ 1) = 3 x 2 x 4 = 24
3. The number of factors of 60 is -
- Option : B
- Explanation : Prime factors of 60 = 2 x 2 x 3 x 5 = 22 X 31 x51 ∴ Number of factors = (2 + 1) x (1 + 1) x (1 + 1) = 3 x 2 x 2 = 12
4. Find the sum of first 4 multiples of 9.
- Option : B
- Explanation : First 4 multiples of 9 are as follow 9 x 1 = 9, 9 x 2 = 18, 9 x 3 = 27 and9x4=36 ∴ Sum of first 4 multiples of 9 = 9 + 18 + 27 + 36 =90
5. The total number of prime factors which are contained in (30)6 is
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