# Thread: Functions and a random question

1. ## Functions and a random question

Basically, I had this work due in by tomorrow and have gone as far as I can with it - So Im left with stuff I dont know how to do. Ill be pressing on with it through the night, but Ive skimmed over it and found the following that I will need some help with:

(8) An engineering firm buys in nuts, bolts and washers for the following prices:

nuts = 8p each
bolts = 12p each
washers = 3p each

Over 3 months a total of 1520 nuts, bolts and washers are purchased for a price of £99:80 (ninety nine pounds and eighty pence). If 20 more nuts than bolts are purchased, how many types of each item are purchased in 3 months?
Done the other 2, just this random question left.

2. For your second one when you have functions "composed" of each other, all you do is "put them in" each other. For example, if $\displaystyle f(x)=x^2$ and $\displaystyle g(x)=\sin(x)$ then $\displaystyle f(g(x))=\left(\sin(x)\right)^2$

3. Originally Posted by Mathstud28
For your second one when you have functions "composed" of each other, all you do is "put them in" each other. For example, if $\displaystyle f(x)=x^2$ and $\displaystyle g(x)=\sin(x)$ then $\displaystyle f(g(x))=\left(\sin(x)\right)^2$
Cheers, helped alot! 1/3 down

The answers I got for the 3 (If anyone feels like confirming for me):

g(f(x))= 2-3(x-2)^2
f(h(g(x)))= (1+4(2-3x^2))+2
h(g(f(x)))= 1+4(2-3(x+2)^2)

thanks once again mathstud (Y)

4. Just the random question annoying me now. Thanks to mathstud Ive finished one and figured out the other myself.

Hope I can get this last one figured out - Its really bugging me on how anyone can go about completing it

If not, its only 1 question and Im sure I can live with it :P!

5. Haha this may be a really stupid question but are there 10 pence in a pound?

6. Originally Posted by Mathstud28
Haha this may be a really stupid question but are there 100 pence in a pound?
Yep :P