answer: henri must make 160 brownies.
work:
set up as a system of equations.
[tex]\frac{40}{x}[/tex] = [tex]\frac{25}{100}[/tex]
now, cross multiply to solve.
25(x) = 40(100)
25x = 4,000
now divide 4000/25.
4000/25 = 160.
40 is 25% of 160, so he must make 160.