CDS 2026 (I) Elementary Mathematics, question 25

Topic: HCF and LCM

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Q25

What is the LCM of 3.63.6, 0.0090.009, 0.270.27 ?

  1. (a) 5.45.4
  2. (b) 10.810.8Correct answer
  3. (c) 16.216.2
  4. (d) 21.621.6

Solution.

Answer: (b) 10.810.8

  1. Scale all three numbers by 1000 to obtain 3600, 9 and 270.
  2. Their prime factors give LCM=24×33×52=10800LCM = 2^{4} \times 3^{3} \times 5^{2} = 10800.
  3. Divide by 1000 to return to the original scale.
  4. 8.
  5. Check: 10.8/3.6=3,10.8/0.009=120010.8/3.6 = 3,10.8/0.009 = 1200 and 10.8/0.27=4010.8/0.27 = 40.