各位知識朋友 , 入黎幫我手 ar !!! ( 數學 F.1 ) (46)

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!

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?