LCM is the multiple of the highest power of prime factors in two or more numbers. Example: LCM of 9, 15, and 25 is 225, which is the multiple of the highest power of prime factors in 9, 15, and 25 (32 x 52).
Yes an No. You can have blood type AB in following situations: AO+ BO AA+BB AB+AB So there's more possible ways to get type AB other than the combination of ABs.