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InterviewSolution
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6.Explain why 7 x 1 113 + 13 and 7 × 6 x 5 x 4 x 3 x2 x 1 + 5 are composite numbersd sort field Sonia takes 18 minutes to drive one round |
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Answer» By definition, A composite number is a positive integer that has a factor other than 1 and itself. Now considering your numbers, 7×11×13+13 may be written as,13*[(7*11)+1] i.e. 13 * (78). So other than 1 and the number itself, 13 and 78 are also the factors of the number. Further, 78= 39 x 2. So, 39 and 2 are also it's factors. So this number is definitely not prime. Hence its composite number. Similarly, 7×6×5×4×3×2×1+5 can be written as 5*[(7×6×4×3×2)+1], i.e. 5 * (1009). So, other than the number and 1, it have 5 and 1009 as it's factors too. So it is also a composite number. |
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