Answer:
2X2x2x5
Step-by-step explanation:
This is the answer
Let's find the required ratios first: to get to the relative percentages, we'll simply have to multiply by 100.
Since there are 16 girls, 10 boys and 9 adults, there are

people in total.
So, the ratio of girls is

The ratio of boys is

The ratio of adults is

ANSWER
The correct choice is A.
EXPLANATION
The given cosine function is:

This function has an amplitude of 2.
Hence it must have range,
-2≤f(t)≤2
It has a period of

Hence the function must complete one cycle on the interval,
[0,½π],
[½π,π],
etc.
The negative sign shows a reflection in the y-axis but since the cosine function is even, the function retraces itself.
The correct choice is A