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各位知識朋友 , 入黎幫我手 ar !!! ( 數學 F.1 ) (46)

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各位知識朋友 , 入黎幫我手 ar !!! 我有幾條數學問題唔識 , 幫手解答 ar( 數學 F.1 )!!!!!!!!!!!!!!!( 只要算式 ) 1.Kiki ' s father is now 46 years old. 8 years later, kiki ' s father will be 2 times as old as her. Find the age of Kiki now. 更新: 2.For the electricity bill, water bill and gas bill received last month, Mr. Ho paid $1000 more on the electricity bill 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 $2080, how much was the electricity bill? 更新 2: henrychoi888 , 咪玩野!!!!

最佳解答:

1. Let Kiki ' s present age be x. 2(x+8) = 46 + 8 2(x+8) = 54 x+8 = 27 x = 19 Kiki is 19 years old now. 2. Let $x be the gas bill. [gas bill] + [water bill] + [electricity bill] = 2080 x + (2x - 160) + [(2x - 160) + 1000] = 2080 5x - 320 + 1000 = 2080 5x = 1400 x = 280 The electricity bill: 2(280) -160 + 1000 = 1400 The electricity bill was $1400. 有錯請指正!

其他解答:

1)Let x be the age of Kiki now. Then his father's age will be 2(x+8) 8 years later. 2(x+8)=46+8 2x+16=54 2x=38 x=19 So the age of Kiki is 19 now. 2)Let $x be the amount of the gas bill? Then the amount of the water bill was $(2x-160) and The the amount of the electricity bill was $[(2x-160)+1000] The total amount was ${x+(2x-160)+[(2x-160)+1000]} {x+(2x-160)+[(2x-160)+1000]}=2080 x+2x-160+2x-160+1000=2080 5x+680=2080 5x=2080-680 5x=1400 x=280 The the amount of the electricity bill =2(280)-160+1000 =560-160+1000 =1400|||||1) Let X for the age of Kiki 8 years later. 46+8 =2X 54=2X X=27 so, the age of Kiki now= 27-8 =19 2)|||||Let x be the Kiki's current age 2 (x + 8) = 46 + 8 = 54 x + 8 = 54/2 = 27 x = 19 Kiki is 19 years old. 2. Let $x be the amount of the electricity bill, $y be the amount of the water bill, and $(2080 - x - y) is the amount of the gas bill x - y = 1000 ... [1] y = 2(2080 - x - y) - 160 ... [2] From [1], y = x - 1000 ...[3] Put [3] into [2], x - 1000 = 2(2080 - x - (x - 1000)) - 160 x - 1000 = 2(3080 - 2x) - 160 x - 1000 = 6000 - 4x x + 4x = 1000 + 6000 5x = 7000 x = 1400 The electricity bill was $1400.|||||1. 46*2/8 =11.5 Kiki 的年齡是11歲|||||各位知識朋友 , 入黎幫我手 ar !!! ( 數學 F.1 ) (46) 各位知識朋友 , 入黎幫我手 ar !!! 我有幾條數學問題唔識 , 幫手解答 ar( 數學 F.1 )!!!!!!!!!!!!!!!( 只要算式 ) 1.Kiki ' s father is now 46 years old. 8 years later, kiki ' s father will be 2 times as old as her. Find the age of Kiki now. 2.For the electricity bill, water bill and gas bill received last month, Mr. Ho paid $1000 more on the electricity bill 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 $2080, how much was the electricity bill?
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