1.一艘潛艇在海面下200m處下降了80m後，再上升100m。求潛艇最後與海面的距離。
2.彼得的年齡是瑪莉的2倍，若他們年齡之和為36，求彼得三年後的年齡。
3.The difference of 2 positive numbers is 120.If 1 number is 4 times the other,findthe 2 numbers.(只想知點列式)
i need the steps and the answers.
ThZZZZZ
mathssssss
2007-11-12 12:19 am
回答 (2)
2007-11-12 12:36 am
✔ 最佳答案
1. 200m + 80m - 100m = 180m 2. let y be mary's age.
mary = y
peter = 3y
mary + peter = 36
y + 3y = 36
4y = 36
y = 8
therefore, mary = 8 years old, and peter = 24 years old
thus, peter three year later will be 27 years old ( 24 + 3 )
3. let one positive number be a, the other be b
formula 1 : a - b = 120
a = b + 120
formula 2 : a = 4b
therefore, sub. formula 2 to formula 1
4b = b + 120
3b = 120
b = 40
sub. b = 40 to formula 1
a - 40 = 120
a = 160
thus, the number is 40 & 160
2007-11-12 12:40 am
1) -200-80 +100= -180 即係海面下180m
2)設彼得是p and 瑪莉是m.
p=2m
p+m=36
p=24, m=12
彼得=24+3=27 #
3)Let the two numbers be X and Y respectively.
X-Y=120
X=4Y
120+Y=4Y
so,Y=40,X=160
2)設彼得是p and 瑪莉是m.
p=2m
p+m=36
p=24, m=12
彼得=24+3=27 #
3)Let the two numbers be X and Y respectively.
X-Y=120
X=4Y
120+Y=4Y
so,Y=40,X=160
參考: me.....^^
收錄日期: 2021-04-13 18:22:15
原文連結 [永久失效]:
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