The question states that if an even number comes up then Joe will win 5 times of the number that shows up for example, if 2 comes up he will win 5×2 dollars i.e., 10 dollars. If an odd number shows up he will lose 10 times the number which i.e. if 1 shows up he will lose 1×10 = 10 dollars
It says in the question that Joe tosses a 3 which is an odd number so he will lose 10 times of 3
LCM the last common multiple. the greatest common factor is the biggest number that will go into the 2 numbers so it can be no bigger than the 2 numbers. the LCM is larger than at least one of them