f.1 mATHSSS

[匿名]

2010-08-22 10:46 pm

After mixing 240 g of sugar solution with 45% concentration ( i.e 45g sugar per 100g of sugar solution) with 260 g of sugar solution with 35% concentration, find the percentage in concentration of the sugar solution.

更新1:

2.Among all visitors ,54% of male visitors and 70% of female visitors are local people. If the number of non-local male and female visitors is 598 and435 respectively on that day, how many visitors are there 3.If 4x+y=3x+5y, find x:y

回答 (1)

STEVIE-G™

2010-08-23 3:56 am

✔ 最佳答案

1)
The weight of sugar in 240 g of sugar solution=240*45%=108g
The weight of sugar in 260 g of sugar solution=260*35%=91g

The percentage in concentration of the sugar solution
=(108+91)/(240+260)*100%
=39.8%

2)
54% of male visitors and 70% of female visitors are local people
=> 46% of male visitors are non-local
=> 30% of female visitors are non-local

Male visitors=598/0.46=1300
Female visitors=435/0.3=1450

So, the total visitor number is 1300+1450=2750.

3)
4x+y=3x+5y
4x-3x=5y-y
x=4y
x/y=4

So, x:y=4:1

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