1.$5400 is divided among three persons:A,B and C.A gets twice the amount of B, while C gets $600 more than 3 thimes B's amount. How much does each of them get?
2.Two cars A and B 250 km apart are travelling towards each other on the same road. Car A travels at 55 km/h while car B travels at 70 km/h .
(a). When will they meet on the road?
(b). Find the distance each car travels before they meet.
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2007-12-27 11:49 pm
回答 (2)
2007-12-28 12:32 am
✔ 最佳答案
1.let x be the money that A gets
let y be the money that B gets
let z be the money that C gets
so
x=2y ......(1)
z=600+3y .......(2)
x+y+z=5400 ......(3)
sub(1),(2)into(3) 2y+y+600+3y=5400
6y=4800
y=$800
x=$1600
z=$3000
2(a)
let x be the number of hours the two cars travel
so 55x+70x=250
25x=250
x=2
They will meet on the road 2 hours later
(b)
car A travels=55x2=110km
car B travels=70x2=140km
2007-12-29 16:09:19 補充：
sorry, i have made a mistake2(a)should be 125x=250
參考: 自己計
2007-12-28 12:25 am
1.let the amount got by B be x
so that the amount got by A is 2x
the amount got by C is 3x+600
x + 2x + 3x+600 = 5400
6x = 4800
x= 800
so B got $800
A got $800 x 2 = $1600
C got $800 x 3 +600 = $3000
2a. 250/(55+70) = 2hours
b. A travel 2 x 55 = 110 km
B travel 2 x 70 = 140 km
so that the amount got by A is 2x
the amount got by C is 3x+600
x + 2x + 3x+600 = 5400
6x = 4800
x= 800
so B got $800
A got $800 x 2 = $1600
C got $800 x 3 +600 = $3000
2a. 250/(55+70) = 2hours
b. A travel 2 x 55 = 110 km
B travel 2 x 70 = 140 km
收錄日期: 2021-04-16 12:29:46
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