1.For the electricity bill, water bill and gas bill received last month, Mr. Ho paid $1 000 more on the electricity cill than on the water bill , and the water bill was $160 less than 2 times the gas bill .If Mr. Ho paid a total amount of $2 080, how much was the electricity bill?
2.Write down the next three terms of the sequence -12,6,-3,........
幫手計2條中一既數學題(~超急~)plz
2007-04-13 8:49 pm
回答 (2)
2007-04-13 8:55 pm
✔ 最佳答案
1. Let E, W, G be the amount of electricity bill, water bill and gas bill respectively.He paid $1 000 more on the electricity cill than on the water bill
so E = 1000 + W
the water bill was $160 less than 2 times the gas bill
so W = 2*G - 160
i.e. W + 160 = 2G
G = W/2 + 80
paid a total amount of $2 080
so E + W + G = 2080
(1000 + W) + W + (W/2 + 80) = 2080
5W/2 = 1000
5W = 2000
W = 400
so E = 1400, G = 280
2. -12, 6, -3, +3/2, -3/4, +3/8,...
2007-04-13 9:12 pm
1.
Let $E, $W, $G be the amount of electricity bill, water bill and gas bill respectively.
E = W+1000
W = E-1000 ----(1)
W = 2G-160
From (1),
E-1000 = 2G-160
E-840 = 2G
G = E/2-420 ---(2)
E + W + G = 2080
From (1) and (2),
E + (E-1000) + (E/2-420) = 2080
5E/2 -1420 = 2080
5E/2 = 3500
E = 1400
2.
As fraction
3/2 , -3/4, 3/8
As decimal,
1.5, -0.75, 0.375
Let $E, $W, $G be the amount of electricity bill, water bill and gas bill respectively.
E = W+1000
W = E-1000 ----(1)
W = 2G-160
From (1),
E-1000 = 2G-160
E-840 = 2G
G = E/2-420 ---(2)
E + W + G = 2080
From (1) and (2),
E + (E-1000) + (E/2-420) = 2080
5E/2 -1420 = 2080
5E/2 = 3500
E = 1400
2.
As fraction
3/2 , -3/4, 3/8
As decimal,
1.5, -0.75, 0.375
參考: 自己
收錄日期: 2021-04-26 13:34:35
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