平均數!!!!!!!!!!!!!!!!

1.86x3-(90+78)=258-168=90

2.725x3-810x2=2175-1620=555

3.(42.5x3+28x2)÷5=(127.5+56)÷5=183.5÷5=36.7

4.(62.8x4+8x4)÷4=(251.2+32)÷4=283.2÷4=70.8

5.20-(20x4)÷5=20-80÷5=20-16=4

第一條~=90
第二條~=555
第三條~=36.7
第四條~=23.7
第五條~=4

1.(86x3-90-78)分 =90分 解:首先將三科我平均分x3 = 三科的總分 然後把總分(258)
減數學和英文。
2.(725x3-810x2)元 =555元 725x3=三樣既總數 810x2=其兩樣總數 then相減



由於famliy既關係，我聽日(12月9日)再答埋其餘果D ' 對不起 '

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第一條~86x3-90-78=90
第二條~725x3-810x2=2175-1620=555
第三條~(42.5x3+28x2)/5=(127.5+56)/5=36.7
第四條~(62.8+8x4)/4=23.7
第五條~20-(20x4/5)=4

1.86*3-90-78
=258-90-78
=168-78
=90

2.725*3-810*2
=2175-810*2
=2175-1620
=555

3.(42.5*3+28*2)/(3+2)
=(127.5+28*2)/(3+2)
=(127.5+56)/(3+2)
=183.5/(3+2)
=183.5/5
=36.7

4.(62.8+8*4)/4
=(62.8+32)/4
=94.8/4
=23.7

5.20-20*4/5
=20-80/5
=20-16
=4

2007-12-08 22:33:50 補充：
No.5 should be(20-20*4/5)/4=(20-80/5)/4=(20-16)/4=4/4=1

1.設欣欣在中文科得到x分
(x+90+78)/3 = 86
x = 90
2.設y為第三副眼鏡的價錢
(y+2 x 810)/3 = 725
y = 555
3.他們的平均體重=(42.5x3+28x2)/5
=36.7公斤
4.如果每個數都加上8,即總共加了4x8=32,所以總和是62.8+32=94.8
A,B,C,D的平均數=94.8/4=23.7
5.足球的價錢=4x20=$80
如果5人平分,每人要付80/5
=$16
所以原本的4位同學可取回20-16=$4

2007-12-08 22:32:53 補充：
第1個回答我睇到至少2個答案唔岩,發問者自行驗算一下就知邊度錯左

2007-12-08 22:47:44 補充：
個足球唔係$80咩?如果係既話,一人攞番$4,咁咪空左$16出來,變左小華同其他人一樣要俾$16 lo如果每人攞$1,變左每人俾$19,小華咪只係俾$4?unreasonable

1. 86x3 - 90 - 78 = 90
2. 725x3 - 810x2 = 555
3. (42.5x3 + 28x2) /5 = (127.5+56)/5 = 36.7
4. (62.8 + 8x4) /4 = 23.7
5. 20x4 - (20x4)/5 = 4


唔知道有無錯ar
我都唔肯定

1) Call Chinese=C, English=E, Maths=M

(C+E+M)/3 = 86

E=78, M=90

(C+168)/3 = 86

C+168 = 258

C = 90

2) Since you are given that the average price of the first 2 pairs of glasses are $810, then treat the 2 pairs of glasses as 1 pair of glasses, with a price of $810.

Call price of 3rd pair of glasses = x

(810+x)/2 = 725

810+x = 1450

x = 640

3) Same as above, treat the 小文,小康和小明 as 1 person, who weighs 42.5kg, and treat 小芬和小玲 as another person, who weighs 28kg.

(42.5+28)/2

= 35.25kg

4) (A+B+C+D) = 62.8, now that each number has 8 added to, it is:-

(A+B+C+D+32)/4

= (62.8+32)/4

=94.8/4

=23.7

5) Before, 4 people together have to pay $20, therefore, each person has to pay:-

20/4 = $5

Now, there are 5 people paying for $20, therefore, each person has to pay:-

20/5 = $4

Therefore, the first 4 people can take back:-

5-4 = $1