Aaa please help - What score do you have to get on a 40 point test to receive a 90% ?

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

The train station clock runs too fast and gains 5 minutes every 10 days. how many minutes and seconds will it have gained at the end of 9 days?

Simplify the expression. -2/5(10+15m-20n)