Plugging in (5 weeks, 40 loads) and (10 weeks, 30 loads) into each choice indicates that f(x) = -2x + 50 is the only correct answer.
First we have to divede the tota of students into the sice of each grop so:

So we can aproximate this to a whole number so:
Let's simplify step-by-step.<span><span>−<span>4.9x</span></span>+<span><span><span>(1.3)</span><span>(0.11)</span></span><span>(0.1)</span></span></span><span>=<span><span>−<span>4.9x</span></span>+0.0143
</span></span>Answer:<span>=<span><span>−<span>4.9x</span></span>+<span>0.0143</span></span></span>
The answer to your question would be A.