Probability to get at least one 6 and at least one 5 in 10 rolls of a die

by Debasish Das   Last Updated September 11, 2019 17:20 PM

I came up across this question and my answer to this was 1 - (4/6)^10 (i.e. 1 - probability that no 6 and no 5 appears) However the answer given is 1 - 2* (5/6)^10 (how ?)

Is my interpretation of NOT(at least one 6 and at least one 5) = No 6 and No 5 wrong ? Should it be No 6 or No 5 instead ? (DeMorgan's Law need to be applied here ?)

Thanks !