Please help me... (1 Viewer)

[Jerry]

Hi all, well, term one is almost over and i have yet another test coming up. We have been given revision questions, and im a little stuck on three of them.

1) The amount of $5000 is invested at 8%. How much more money must be invested at 11% in order to have a 10% rate of reutrn on the total amount of money invested.

2) The Banana Computer Company makes two types of computers, the Orange Computer and the Lemon Computer. In their manufacture, two types of circuit are used, circuit A and circuit B. Each Orange computer uses 1 circuit A and 2 circuit B's. Each Lemon COmputer uses 2 circuit A's and 1 circuit B. There are 10 circuit A's and 8 circuit B's available each hour. Represent the possible number of each type of computer that can be made per hour.

now, this last question looks really simple, but i can only get half way through it

ab+2a+4b-2

If someone out there that is really smart actually answers these questions, can you please show working so i know how to do it.

Thanx,

Jerry

 

[kini mini]

Originally posted by Jerry

1) The amount of $5000 is invested at 8%. How much more money must be invested at 11% in order to have a 10% rate of reutrn on the total amount of money invested.

Welcome to the board Jerry .

<sigh> Just as I finish my financial maths work for Wednesday's tutorial, someone asks a question on it .

Let the additional amount of money be $x.

So 5000*0.08 + x*0.11 = 0.10*(5000 + x)

You can solve for x from here . All I've done is translate your question into an equation, if you don't understand what i did then just ask.

2) The Banana Computer Company makes two types of computers, the Orange Computer and the Lemon Computer. In their manufacture, two types of circuit are used, circuit A and circuit B. Each Orange computer uses 1 circuit A and 2 circuit B's. Each Lemon COmputer uses 2 circuit A's and 1 circuit B. There are 10 circuit A's and 8 circuit B's available each hour. Represent the possible number of each type of computer that can be made per hour.

Represent? I suppose this means a graph or table? You can start by saying "suppose I make as many Lemons I can make per hour and then use what's left to make Oranges", then reducing the number of lemons by one and seeing how many extra oranges you can make.

now, this last question looks really simple, but i can only get half way through it

ab+2a+4b-2

I think you haven't written this correctly Jerry - do you mean ab+2a+4b=2? Even then it's insoluble as you have one equation and three terms, you can only find them in terms of each other.

 

[Jerry]

Thanx Kini,

I'm guessing that * stands for times.

Im not sure what it means by represent, i think its ment to say something like how many of each computer can be made per hour, it is out of some stupid text book that our teachers made up!

As for the last one, thats what i thought! the furthest i can get on it is

a(b+2)+4b-2,

it just doesnt factorise any further really! i thought it was a really stupid question.

 

[kini mini]

Originally posted by Jerry
I'm guessing that * stands for times.

That's right

Im not sure what it means by represent, i think its ment to say something like how many of each computer can be made per hour

Just make a table then, it's the easiest thing to do .

As for the last one, thats what i thought! the furthest i can get on it is
a(b+2)+4b-2,

What are the exact instructions about this question? . It doesn't make sense.

 

[Jerry]

lol, sorry kini.

All it says is "Factorise"

I sat there for about an hour and came up with:

ab+2a+4b-2

= a(b+2)+4(b-1/2)
= (b+2)(b-1/2)(a+4)
= b squared(-0.5b + 2b)(-1)(a+4)
= b squared+1.5b+a+3

I'm not exactly sure if this is right, but oh well.

And the computer one, i dont think they want a tabel drawn because it is all about the equations and stuff. Ah well, doesn't matter, i'll just ask my teacher in the study time before the test, thanx SOOOOOOOOOOOOOOOOOOOOOOO much for your help though!

 

[kini mini]

That's alright

How did your test go?

 

[Jerry]

Well, I feel it went okay, but i will find out when the results come. it was outta 43 and i didnt do 6 marks of questions, so i hope i went ok but thanx anyway, i'll post my results as soon as i get them, probably in about 2 weeks.

 

[:: ck ::]

Originally posted by Jerry
lol, sorry kini.

All it says is "Factorise"

I sat there for about an hour and came up with:

ab+2a+4b-2

= a(b+2)+4(b-1/2)
= (b+2)(b-1/2)(a+4)
= b squared(-0.5b + 2b)(-1)(a+4)
= b squared+1.5b+a+3

I'm not exactly sure if this is right, but oh well.

And the computer one, i dont think they want a tabel drawn because it is all about the equations and stuff. Ah well, doesn't matter, i'll just ask my teacher in the study time before the test, thanx SOOOOOOOOOOOOOOOOOOOOOOO much for your help though!

its wrong

 

[KeypadSDM]

As far as my mathematical knowledge can tell

for ab + Xa + Yb + C = 0 to be factorisable (where a and b are the variables, and X, Y and C are constants) XY = C

In yours though ab+2a+4b-2=0;
2 * 4 =/= -2

However an equation can be formed from yours:
ab+2a+4b-2 = 0

ab + 2a + 4b - 2 = 0
ab + 2a + 4b + 8 = 10 ( +10 to both sides)
a(b + 2) + 4(b + 2) = 10
(a + 4)(b + 2) = 10
a + 4 = 10/(b + 2)
a = 10/(b + 2) - 4

not factorisable, but solvable.