Question 625959
For the situation, it makes sense that the total amount collected (with equal amounts given by all contributing) would be the number of players contributing times the amount given by each one.
So n times c would be the amount collected, which must be the price of the gift, so it is a constant. The function must be {{{nc=constant}}}. That tells you it must be choice A or choice C. 
 
If you start multiplying the numbers in the table you will now the constant.
The easiest multiplication first:
{{{10*20=200}}}
Then, the function is {{{nc=200}}}
That tells you to chose answer C.
 
If not pressed for time in a test, you keep multiplying.
{{{5*8=200}}}
{{{8*25=200}}}
{{{15*13=195}}}
So the function is confirmed as {{{nc=200}}}.
 
If it was not multiple choice, you would have to solve
{{{nc=200}}} with {{{n=40}}} to find how much each person must give (c) if all 40 players contribute.
{{{40c=200}}} --> {{{40c/40=200/40}}} --> {{{highlight(c=5)}}}