Extension question (provide a full explanation of your method(s):
ann and ben are playing a game with a pile of counters.
the rules are :
(a) at each turn a player may remove 1, 2 or 3 counters
excepting the number removed by the opponent on the
previous turn;
(b) the player who makes the last legal move wins ;
rule (b) automatically means that if there is one counter
left and the player can't move, then the opponent wins.
can ann win if she is presented with 4 counters ?
show that ann can always win from a pile of 6 counters
regardless of ben's previous move.

Ann has little chance to win if she is presented with 4 counters.

Ann can always win from a pile of 6 counters.

(both are explained below)

Step-by-step explanation:

If Ann  is presented with 4 counters, and

1. if she takes out 3, she will lose since the opponent will  pull out 1 and the last one.

2. if she takes 2 her opponent will take out 1 and she can't pull out the last 1 since her opponents last move was to pull out 1  counter so she will lose.

3. If she takes out 1 and her opponent takes out 3 in the next move she loses.

but if instead of 3 her opponent takes out 2 and in the last move Ann takes out the last 1  then she will win.

So, If Ann is presented with 4 counters she has little chance to win provided in the move just before, her opponent didn't move 1 counter.

Now,

if there is 6 counters to Ann, and

1., if Ben's  previous move was 1 then Ann can win if she takes out 3 or 2.

If she takes out 3 Ben can take out 1 or 2 and in the last move she will take out 2 or 1 (respectively) and winning the game.

If she takes out 2 Ben can  take out 1 or 3 and in the last move Ann wins by pulling out 3 or 1 respectively.

2. if Ben's  previous move was 2 then Ann can win if she takes out 1 or 3.

If she takes out 1 Ben can take out 2 or 3 and in the last move she will take out 3 or 2(respectively) and winning the game.

If she takes out 3 Ben can  take out 1 or 2 and in the last move Ann wins by pulling out 2 or 1 respectively.

2. if Ben's  previous move was 3 then Ann can win if she takes out 1 or 2.

If she takes out 1 Ben can take out 2 or 3 and in the last move she will take out 3 or 2(respectively) and winning the game.

If she takes out 2 Ben can  take out 1 or 3 and in the last move Ann wins by pulling out 3 or 1 respectively.

total amount of money that he should pay if he has not used his duty free exemption is $98

step-by-step explanation:

given a united states citizen returning to the states declares the following items at the customs office: 3 shirts at $8.50 each 2 dresses at $27.50 each 1 pair of gold cuff links at $17.50 per pair. we have to find how much he pay

cost of 3 shirts if one cost at $8.50 is

cost of 2 dresses if one cost at $27.50 is  

cost of 1 pair of gold cuff at $17.50

so, total amount of money that he should pay if he has not used his duty free exemption is   $25.5+$55+$17.50=$98