難題
一、一個(gè)袋中裝有2個(gè)黃球和2個(gè)紅球,任意摸出一個(gè)球后放回,再任意摸出一個(gè)球,請(qǐng)和你的同伴合作,記錄實(shí)驗(yàn)10次,50次,100次,150次,200次后,第一次摸到紅球的次數(shù)n1,兩次都摸到紅球的次數(shù)n2.
試驗(yàn)次數(shù)n 10次 50次 100次 150次 200次
n1（頻數(shù)）
n1/n（頻率）
n2（頻數(shù)）
n2/n（頻率）
你們能發(fā)現(xiàn)什么現(xiàn)象?第一次摸到紅球的概率估計(jì)值是多少?兩次都摸到紅球的概率估計(jì)多少?
二、 James gets up at five to seven.His parents and his little twin sisters go travelling in France and he has to look after himself at home.He opens the fridge,but he finds there are only two hamburgers in it.He decides to have breakfast in the restaurant on the other side of the street.He sits at a table,the waiter comes up and says ,"Can I take your order,James?"
But you don't show your menu(菜單) to me,Mr Hunt."says the boy.
"Oh,sorry!I forget it.Here it is."
James looks at the menu carefully.
Bread ￥1.30 Sandwich ￥1.80 Hamburger ￥2.00 Pizza ￥2.40
Egg ￥0.30 Milk ￥0.50 Coffee ￥0.70 Coke ￥0.30
James takes out his wallet and finds there is only 6.50 yuan in it.
"Well."says Mr Hunt."What about a hamburger,a pizza,two eggs and a glass of Coke?"
"Oh,no."says the boy."I will buy a picture-book this afternoon.It's 1.50 yuan."
"I see,"says the waiter.And then he brings the boy a nice breakfast.
根據(jù)短文內(nèi)容,完成下列句子,每格所填詞數(shù)不限
1、hopes to pay ________ for his breakfast.
2、James maybe has two eggs,a pizza,a cup of coffee and a piece of bread for _________.
希望回答者能給出答案的理由.
數(shù)學(xué)題目中“第一次摸到紅球的次數(shù)n1,兩次都摸到紅球的次數(shù)n2”這句話是什么意思?否則沒法填表格啊