11 boys and 8 girls because you divide it in half the add 2 and subtract 1. That isn't the wy you are supposed to do it but it works and makes since in my head.
(8+15+8+3+12)/2+1=24th number will be median
So median is gonna be 21
If period of

is one-half the period of

and
<span>

has a period of 2π, then

and

.
</span>
To find the period of sine function

we use the rule

.
<span /><span />
f is sine function where f (0)=0, then c=0; with period

, then

, because

.
To find a we consider the condition

, from where

.
If the amplitude of

is twice the amplitude of

, then

has a product factor twice smaller than

and while period of

<span> </span> is 2π and g(0)=0, we can write

.
Looks good! You have the right answers.
However, the graph for 12 and 15 is inaccurate! Because he starts from a stop sign/stop light, the graph's speed should start from the origin!
Not to confuse you or anything, but this means the graph does not follow the description of the problem. Please let your teacher know so s/he can fix the worksheet.