The LCM of 6, 72 and 120 is:
A180
B240
C720
D360
Answer & Solution
Correct answer: D. 360
1. Write each number as a product of primes: 6 = 2 x 3.
2. 72 = 2^3 x 3^2 and 120 = 2^3 x 3 x 5.
3. The LCM takes the highest power of every prime that appears: 2^3, 3^2 and 5.
4. So LCM = 8 x 9 x 5 = 360.
5. 180 misses a factor of 2 and 240 misses a factor of 3, so neither is a multiple of 72.
_Source: NCERT Class 10 Maths, Ch 1 'Real Numbers', S1.2 The Fundamental Theorem of Arithmetic_
Related questions
Before applying any solving method, an equation must first be written in its:Which two methods of solving quadratic equations are worked through in the examples?Because 2401 is the square of 49, that equation has roots that are:A number of toys problem leads to 2x squared plus x minus 300 equals 0. Its discriminant iThe roots of a quadratic equation are the same as the zeroes of the corresponding:The values of x that satisfy a quadratic equation are called its:A method that rewrites the equation so one side becomes a perfect square is called:The roots of x squared plus 4x minus 5 equals 0 are: