# Need some help with a few questions that have been annoying me

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• September 3rd 2007, 11:48 AM
Xplicit
Need some help with a few questions that have been annoying me
1) Make s the subject of the formula below

v= s (w+x) (thats "S" over "3")
--
3

2)Simplify Fully

12s squared t squared
OVER
16st cubed

3) Solve the simultaneous equasion

3p+q=11.25
p-2q=7.25

4)Show that a solution of the equation
x Cubed- 10x=35
Lies between 4.2 and 4.3

5)Marks jigsaw puzzle contains 3 types of pieces
>Corner pieces-- 0.008
>Straight edge pieces--0.164
>Middle pieces-- unknown

Mark picks a piece out at random. The probability's of picking a corner or straight edge piece are shows above

There are 500 pieces in marks jigsaw puzzle
How many middle pieces are there?

Thanks in advance to anyone who helps in and if you can will you please show me some formula so i can learn from my mistakes

:>:>
• September 3rd 2007, 12:04 PM
red_dog
1) $\displaystyle v=\frac{s}{3}(w+x)\Rightarrow s=\frac{3v}{w+x}$

2) $\displaystyle\frac{12s^2t^2}{16st^3}=\frac{3s}{4t}$

3) $\left\{\begin{array}{ll}3p+q=11.25\\p-2q=7.25\end{array}\right.$
Multiply the first equation by 2, then add the equations.
We have $7p=29.75\Rightarrow p=4.25$.
Now, plug p in any equation and find q.

4) Plug x=4.2 and x=4.3 in equation and probably you'll obtain one negative value and one positive value.

5) Let x be the number of middle pieces.
The probability to pick one is $\displaystyle\frac{x}{500}$.
On the other hand, the same probability is 1-0.008-0.164.
Equalize the two values and solve for x.
• September 4th 2007, 11:52 AM
Xplicit
Thanks