Can someone please explain how to do this problem?

A regional soccer tournament has 64 participating teams. In the first round, the number of games played decreases by a factor of one half. Find a rule for the number of games played in the regional soccer tournament.

I tried using the formula An=a1(r)^n-1 but I don't think that's right. I also tried using the formula a1(1-r^n/1-r). Am I doing something wrong or not using the right formula?

The second formula is correct

The games played are 32,16,8,4,2,1
a1=32, r = 1/2 and there are 6 rounds played.

32(1 - 1/2^6)/(1 - 1/2)
= 32(63/64)/(1/2)
= 63

To find a rule for the number of games played in the regional soccer tournament, let's break down the problem step by step.

In the first round, the number of games played decreases by a factor of one half. This means that after the first round, there will be half as many games as there were before.

Let's denote the number of games played in the first round as G1. After the first round, the number of games remaining will be G1/2.

Now, if we look at the second round, the number of games played will again decrease by a factor of one half. This means that after the second round, there will be half as many games as there were in the previous round.

So, the number of games played after the second round will be (G1/2)/2 = G1/4.

Following this pattern, we can see that after each subsequent round, the number of games played will be half of the previous round. This can be expressed using exponents.

Let's represent the number of games played after the nth round as Gn. We can write the relation between the number of games after each round in terms of the first round as:

Gn = (G1) * (1/2)^(n-1)

Now, we need to find the value of G1, the number of games played in the first round. We are given that there are 64 participating teams in the tournament, and in the first round, each team plays one game.

Since each team must play against another team, the number of games in the first round will be half the total number of teams, which is 64/2 = 32.

Therefore, G1 = 32.

Now we can substitute the value of G1 into the previously derived relation:

Gn = 32 * (1/2)^(n-1)

This formula represents the rule for the number of games played in the regional soccer tournament, where Gn is the number of games played after the nth round, and n is the round number.

So, to find the number of games played, you can use the formula Gn = 32 * (1/2)^(n-1), where n represents the round number.