The LCM of 15x3 y4 and 12x2y5 is:
- AOption (a)
25x3 y5
- BOption (b)
15x3 y5
- COption (c)
12x3 y3
- DOption (d)
60x3 y5
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Correct answer
60x3 y5
Why this answer is correct
Shortcut Trick
Identify the LCM of numerical coefficients: LCM(15, 12) = 60.
For variables, take the highest power of each: xmax(3,2) = x3 and ymax(4,5) = y5.
Combine them: 60 × x3 × y5.
∴ The correct answer is 60x3y5.
Alternate Method
Given: First expression = 15x3y4 and Second expression = 12x2y5.
Formula Used: LCM of algebraic terms = (LCM of numerical coefficients) × (Product of variables with highest powers).
Calculations:
⇒ Prime factorization of 15 = 3 × 5
⇒ Prime factorization of 12 = 22 × 3
⇒ LCM of (15, 12) = 22 × 3 × 5 = 60
⇒ Highest power of variable x in both terms = x3
⇒ Highest power of variable y in both terms = y5
⇒ Combined LCM = 60 × x3 × y5 = 60x3y5
∴ The correct answer is 60x3y5.
Additional Information
HCF of Algebraic Expressions
To find the HCF, take the HCF of numerical coefficients and multiply by the lowest power of common variables.
Product Rule
For any two expressions A and B: A × B = HCF(A, B) × LCM(A, B).
LCM of Fractions
LCM = (LCM of Numerators) ÷ (HCF of Denominators).
















