joywzy

.(1.000001X0.99999)-(1.000002X0.999998)
my ans: 3*(10)^(-10)

(1.00001)^2*(0.99999)^2-(1.00002)^2*(0.99998)^2
my ans: 6*[(10^(-10)-10^(-20)}

joywzy

6,A/B=9/10, 答案错了

其它题我做了,答案没错

joywzy

38)应用题，A的篮子里有1个chicken sandwich和2个cheese sandwich。B有3个chicken sandwich和5个cheese sandwich。问BOTH A AND B 随机取出的是chicken sandwich的概率是多少？
（1/3）*（3/8）=1/8，数字不确定。
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这题应该是4/(1+2+3+5)=4/11

joywzy

对不起,第1题是我算错了,是X/3

3某东西sell at price 20 dollors, including tax, 税率是百份P，还包括其他什么费less than C，好象问：不含税的部分小于15吗？A：P等于6，B：C等于5
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(x+c)(1+p)=20
my ans is B

能否详细讲解.谢谢!

joywzy

3某东西sell at price 20 dollors, including tax, 税率是百份P，还包括其他什么费less than C，好象问：不含税的部分小于15吗？A：P等于6，B：C等于5 --------------------------------- (x+c)(1+p)=20 if c=5 , whatever p is , ( even is 0 ) x<=15 , but from the text , p can not be 0 , since there is tax payment ( or you will be fined ....kidding ) so B is sufficient In this aspect, i agree with u but when p=6 or mean tax rate 6% => x+c= 20/7=2.8, and X>0,c>0=>0X,15 so i think A is sufficient I guess A,B is both sufficient Did i make any mistakes?