Find the smallest number that should be multiplied with 54000 to make it a…
2024
Find the smallest number that should be multiplied with 54000 to make it a perfect cube
- A.
04
- B.
05
- C.
03
- D.
27
Attempted by 90 students.
Show answer & explanation
Correct answer: A
Solution:
Step 1: Prime-factorise 54000.
54000 = 54 × 1000 = (2 × 3^3) × (2^3 × 5^3) = 2^4 × 3^3 × 5^3.
Step 2: For a number to be a perfect cube, every prime exponent must be a multiple of 3.
Exponent of 2 is 4. The next multiple of 3 ≥ 4 is 6, so we need 2 more factors of 2 (multiply by 2^2 = 4).
Exponent of 3 is 3 (already a multiple of 3), so no extra 3 is needed.
Exponent of 5 is 3 (already a multiple of 3), so no extra 5 is needed.
Step 3: Multiply by 2^2 = 4. This gives 54000 × 4 = 216000 = 60^3, which is a perfect cube.
Answer: 4