in how many ways can first and second prize be awarded in a contest with 100 people, assuming that each prize is awarded to a different pers

Melody said: Can someone please remind me how to put the last 2 answers into the Input=Result.

 

npr(100,2)  gives 

$${\left({\frac{{\mathtt{100}}{!}}{({\mathtt{100}}{\mathtt{\,-\,}}{\mathtt{2}}){!}}}\right)} = {\mathtt{9\,900}}$$

 

2*ncr(100,2) gives

$${\mathtt{2}}{\mathtt{\,\times\,}}{\left({\frac{{\mathtt{100}}{!}}{{\mathtt{2}}{!}{\mathtt{\,\times\,}}({\mathtt{100}}{\mathtt{\,-\,}}{\mathtt{2}}){!}}}\right)} = {\mathtt{9\,900}}$$

100*99 = 9900

or if you prefer

$$^{100}P_2}$$          $${\left({\frac{{\mathtt{100}}{!}}{({\mathtt{100}}{\mathtt{\,-\,}}{\mathtt{2}}){!}}}\right)} = {\mathtt{9\,900}}$$

or

$$2\times^{100}C_2$$          $${\mathtt{2}}{\mathtt{\,\times\,}}{\left({\frac{{\mathtt{100}}{!}}{{\mathtt{2}}{!}{\mathtt{\,\times\,}}({\mathtt{100}}{\mathtt{\,-\,}}{\mathtt{2}}){!}}}\right)} = {\mathtt{9\,900}}$$

Take your pick!

Can someone please remind me how to put the last 2 answers into the Input=Result.

(Thank you - I have received 'spiritual' help. That is, help from a disembodied human)

I suppose I should look it up but i have the same lazy attitude as many question askers.  It is easier just to ask.  

Thanks Alan - Now 2 people have help me.

I guess I didn't put this big enough. lol

(Thank you - I have received 'spiritual' help. That is, help from a disembodied human)

 

I love the hover display boxes that andre has added for LaTex and Math display.

It should really help people to learn.  I put a number of Rom's outputs over into the LaTex thread but I mustn't have pressed Publish because they are not there.  I will have to enter them all over again! Drats!