Need some help with Probability

Ok, it doesn't conform to the rules of a binomial distribution because p + q =/= 1, but the principle of how it works still applies. The probability of getting 4 scrolls to work and 1 to fail but not break is still P[work] * P[work] * P[work] * P[work] * P[fail w/o break] and since you could have the scrolls appearing in a different order, times it by 5C4.