Traza la gráfica de la funcion dada en el intervalo dado, y localiza el punto donde la gráfica tiene una tangente horizontal. F(x) = x^2 + en [-2, 2]

she will travel a distance in the range of 3 - 11 miles

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.