SAT 2 maths A coin is tossed three times.given that at least one head appears.what is the probability that exactly two heads appear?Answer 3/7 为什么不是3/8?

SAT 2 maths A coin is tossed three times.given that at least one head appears.what is the probability that exactly two heads appear?Answer 3/7 为什么不是3/8? SAT 2 maths level2 A coin is tossed three times.Let A ={three heads occur} and B = {at least one head occurs}.What is P(AUB)答案是7/8P(AUB) = P(A) + P(B) - P(A∩B) = 1/8 + 7/8 - (1/8)(7/8) = 53/64 I sent you a Maths coin a phrase coin. coin the coin was()dirty when i found it in the street.1、a few 2、a bit 3、a bit of 4、little A flip of a coin i find maths a little_ (hard)for youi find maths a little _(hard)for you I want to learn a subject which is called a maths对吗?called maths both sides of a coin 英语翻译School was over and I was both mentally and physically tired.I sat at the very front of the bus because of my anxiety to get home.Sitting at the front makes you stand out like a shiny coin in a pile of dull pennies.Janie,the driver,tries 英语翻译翻译并填空：School was over and I was both mentally and physically tired .l Sat at the very front of the bus because of ____to get home .sitting at the front makes you ____out like a shiny coin in a pile of dull pennies . I failed a Maths exam again.的反义疑问句 I should have a maths lesson.bye这是啥米意思 Every coin has 2 sides. 用所给的正确形式填空 he sat there and -----(read) a book carefully .how about your maths exam I think this is the oldest coin ___ I have ever seen.A.which B.who C.what D.that