Students deliver catalogues and leaflets to houses. One day, they have to deliver 384 catalogues and 1890 leaflets.
Each student can deliver either 16 catalogues or 90 leaflets in 1 hour.
Each student can only work for 8 hours.
All students hired are paid £51.30 per day, even if they don't work a full day.
If the minimum number of students are hired, how much will the wage bill be?

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204

i think the answer is b