歡麗 asked in 教育及參考書教學 · 9 years ago

F.1 English Mathematics 15點 急

1.If 1 - x/2 - x/4 - x/8 = x - 1, then x=

2.What is the value of x for the equation 1/6x - 3 1/2 = -15

3.Divide the sum of 6 and twice then number x by 3 is equal to 6. Which of the following equations represents the above sentence?

4.Subtract half of x from three times x is equal to 10. What is x?

5.Andy spent $82 on buying some mangoes at $4.5 each and x oranges at $2.5 each. He bought 20 mangoes and oranges altogether. The equation for solving the problem is

6.Nancy is twice as old as Peter. After eight years, the sum of their ages will be 94. How old is Nancy now?

Update:

7.Mr. Chan paid $160 for 100 ball pens. If he sells them at $2 each, what is the profit per cent?

8.A book marked at $M was selling price of the book is $120, then M =

9.An article is marked by an increase of 40% on the cost. It is then sold at a discount of 40%. On the whole,

Update 2:

8.A book marked at $M was selling price of the book is $120, then M =

A.96

B.100

C.144

D.150

10.A sold his car to B at a loss of 20%. B sold it to C at a profit of 5%. If C paid $168 000 for the car, find A’s loss.

11.The costs of labour and cloth for making a dress are $500 and $125 respectively.

Update 3:

11.The costs of labour and cloth for making a dress are $500 and $125 respectively. If the cost of labour is increased by 5% and the cost of cloth is decreased by 20%, what is the percentage change in the cost of making the dress?

A.an increase of 5%

B.a decrease of 5%

C.an increase of 10%

Update 4:

D.no change

12.What is the simple interest on $2 400 at 4% p.a. for 2 years?

13.At what rate p.a. simple interest will $7 200 amount to $9 600 in 2.5 years?

14.If the interest rate on a certain sum of money is decreased from 5% p.a. to 4.5% p.a., then the annual interest is decreased by $610.

Update 5:

Find the sum of money.

15.If $2 400 amounts to 2 520 in 15 months by simple interest, what will it amount to in 2 years at the same interest rate?

16.The size of a triangle cannot exceed: A.90°

B.120° C.150° D.180°

1 Answer

Rating
  • c
    Lv 5
    9 years ago
    Favorite Answer

    1.

    1 - x/2 - x/4 - x/8 = x - 1

    1-7x/8=x-1

    15x/8=2

    x=16/15 2.

    if 1/(6x)-(3+1/2)=-15,

    1/(6x)-7/2=-15

    1/(6x)=-23/2

    x=-1/69 if(1/6)x-(3+1/2)=-15,

    (1/6)x-7/2=-15

    (1/6)x=-23/2

    x=-69/23.

    (6+2x)/3=6

    2+2x/3=6

    2x/3=4

    x=6 4.

    3x-x/2=10

    5x/2=10

    x=4 5.

    the number of mangoes = 20-x

    4.5(20-x)+2.5(x)=82

    90-2x=82

    2x=8

    x=4 6.

    let Nancy be y years old now.

    Peter is y/2 years old now. (y+8)+(y/2+8)=94

    3y/2+16=94

    3y/2=78

    y=52Nancy is 52 years old now.

    2011-07-10 14:40:44 補充:

    7.

    Profit percent

    =Profit/cost

    =(Selling price-cost)/cost

    =($2x100-$160)/$160

    =(200-160)/160

    =40/160

    =0.25

    =25%

    8.

    marked price x (1-discount percentage)=selling price

    if the discount percentage is n%,

    $m x (1-n%)=$120

    m=120/(1-n%)

    m=12000/(100-n)

    2011-07-10 14:41:11 補充:

    9.

    let the cost of the article be $y.

    marked price=$y*(1+40%)=$1.4y

    selling price=marked price*(1-40%)=$1.4y*(1-40%)=$0.84y

    On the whole,

    Profit percent

    =Profit/cost

    =(selling price-cost)/cost

    =($0.84y-$y)/$y

    =(0.84-1)/1

    =-0.16

    =-16%

    2011-07-10 14:41:22 補充:

    Profit

    =selling price-cost

    =$0.84y-$y

    =-$0.16y

    (which means a loss of $0.16y)

    2011-07-11 11:20:19 補充:

    the solutions for Q8-16 is in the following links

    you may delete the "???" behind h

    h???ttp://i90.photobucket.com/albums/k278/kkcas/q8-q11.jpg

    h???ttp://i90.photobucket.com/albums/k278/kkcas/q12-q14.jpg

    h???ttp://i90.photobucket.com/albums/k278/kkcas/q15-q16.jpg

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