In a national chess tournament, 40% of the players are eliminated each day. If the tournament starts with 2,000 players, to the nearest integer, how many players will be present at the start of the 5th day of play?

Question

solomonzelman · Answer

the common ratio here would be

1 / 1.4

I think

anonymous · Answer

1 divided by 1.4 ?

anonymous · Answer

what kind of equation do i use for this?

solomonzelman · Answer

I like your username, irrod

I mean times (5/7)  same thing...

ranga · Answer

If 40% of the players are eliminate each day, it means 60% of the players are retained after each day.  At the end of 1st day how many players will remain?

solomonzelman · Answer

I like chess better than math (I used to make money in tournaments) no kidding.

anonymous · Answer

thanks
so is this like an An=A1+9n-1)d kind of equation or what?

ranga · Answer

This is a geometric progression question and not arithmetic progression.  You have to find the 5th term in the GP.

anonymous · Answer

okay , whats the equation for that?

anonymous · Answer

A=ar^(n-1)

?

ranga · Answer

40% eliminated implies 60% (or 0.6) retained.
Start of 1st day -- 2000 players
Start of 2nd day --- 2000 x 0.6
Start of 3rd day --- 2000 x 0.6 x 0.6
....

anonymous · Answer

so when i list my variables does r=.6 or r=.4 ?

ranga · Answer

r = 0.6
a1 = 2000
a5 = ?

anonymous · Answer

so when set up would it look like =2000(.6)^(5-1)

?

ranga · Answer

Yes.

anonymous · Answer

and my answer is 259?

ranga · Answer

Yes.

wolf1728 · Answer

I calculated 259 also

anonymous · Answer

okay thanks guys

ranga · Answer

you are welcome.

anonymous · Answer

@ranga you think you could help me w another ?

anonymous · Answer

part 1: What are the possible number of positive, negative, and complex zeros of 
f(x) = –2x^3 – 5x^2 + 6x + 4 ? 

Part 2: Use complete sentences to explain the method used to solve this equation

ranga · Answer

Familiar with Descartes' Rule of Signs?

anonymous · Answer

positives  i got 1, negatives i got 2 or 0, i don't know how to find the complex ze

ranga · Answer

Correct.  This has 1 positive zero  and 2 or 0 negative zeros.
Since this is a third degree polynomial it must have a total of 3 roots.
Put all the possibilities in a table form:|dw:1396832674948:dw|