Write an explicit formula for an, the nth term of the sequence 27, 21, 15, ….
1 answer:
You might be interested in
Answer:
Step-by-step explanation:
You can split the coins into 3 groups, each of them has 3 coins. Weigh group 1 vs group 2, if one is lighter, that group has the fake coin. If both groups weigh the same, then group 3 has the fake coin.
Continue to split the group that has the fake coin into 3 groups, each group has 1 coin. Now apply the same procedure and we can identify the fake coin.
Total of scale usage is 2
b) if you have coins then you can apply the same approach and find the fake coin with just n steps. By splitting up to 3 groups each step, after each step you should be able to narrow down your suspected coin by 3 times.
Step 1: you narrow down to group of coins
Step 2: you narrow down to group of coins
Step 3: you narrow down to group of coins
...
Step n: Step 1: you narrow down to group of coin
The range of the answer is [-3,infinity) and {yly>=-3}
