Answer:

Step-by-step explanation:
We are given the following in the question:
The numbers of teams remaining in each round follows a geometric sequence.
Let a be the first the of the geometric sequence and r be the common ration.
The
term of geometric sequence is given by:


Dividing the two equations, we get,

the first term can be calculated as:

Thus, the required geometric sequence is

There are 4 boys and 12 students in total. It would be 4/12, but if it was to be simplified, it would be 1/3. The probability of a boy being selected is 1/3.
Answer:
A
Step-by-step explanation:
17 / 12
(12 + 5) / 12
12/12 + 5/12
1 5/12
Step-by-step explanation:
5/10+2/10
7/10
0.7
................