Question 467175
Have to solve the equation 

{{{0.2x^2 + 40x = 2500}}}, or {{{0.2x^2 + 40x - 2500 = 0}}}

==> {{{x = (-40 + sqrt(40^2-4*0.2*-2500 ))/(2*0.2) = ( -40 + 60)/0.4 = 20/0.4 = 50}}} .

So, it is possible for the consultant to earn $2500 in one week, if he would earn $50 per hour.