Find the probability that event a will appear at least three times in four independent tests if the probability of occurrence of event a in one test equal to 0.4

This kind of problems are solved using Bernoulli's distribution. Everytime you have a win/lose scenario, and you know the probability of winning, and you want successes over trials, you have the following probability:

You want the probability of having at least three successes, i.e. you are interested in the cases k=3 and k=4. The corresponding probabilities are

So, the total probability is

it will cost dollar $540

the living room is 3 which means if we divide 325/3 then we get $108

therefore if 1part of the living room cost $108 and 3 costed $325

then total 5part of the room will cost 5*108 which gives $540

answer: the answer is b. i think hope i got it correct

step-by-step explanation: