Least common multiple question

[jfranco23]

If M is the Least Common Multiple of 90, 196 and 300, which of the following is NOT a factor of M?

A. 600
B. 700
C. 900
D. 2100
E. 4900

[devesh99]

LCM is 44100

2*2*3*3*5*5*7*7 = 44100

Ans (A)

[Brent@GMATPrepNow]

If M is the Least Common Multiple of 90, 196 and 300, which of the following is NOT a factor of M?

A. 600
B. 700
C. 900
D. 2100
E. 4900

I thought it might be useful to show one way to find the LCM of large numbers:

[mrsmarthi]

IMO E.

Express each number in prime factors with each prime factor in exponetation notation.

LCM is the product of distinct prime factors having the highest exponents.

90 = 2 * 3^2 * 5
196 = 2^2 * 7^2
300 = 2^3 * 3 * 5^2
-------------------------
LCM = 2^3 * 3^2 * 5^2 * 7^2

Now coming to the ans choices all of them are multiples are 100 = 2^2 * 5^2.

Cancelling this part from the LCM we have 2 * 3^2 * 7^2.

Only E(49) cannot be formed from the above left over of LCM.

[cramya]

Mrs.Marthi,
I think u may have accidentally included an extra 2 in the lcm which led you to E.

Regards,
Cramya