Why Do I Need to Multiply Probabilities in a Binomial Distribution?

[kelvin macks]

please refer to the second line of solution, since we only concerned about the probability of getting number (5) , then why can't I just just say P=(5/6)^5 , why should I times =(5/6)^5 with (1/6)^2 ?

 

[Erland]

(5/6)^5*(1/6)^2 is the probability to get five non-fives followed by two fives, when throwing the die seven times. (5/6)^5 is just the probabability to get non-fives the five first times, regardless of if you get any more fives the two last times.