Question 389588
t = d / r ___ the time for the faster rate is 1/2 hr less


120 / x = [120 / (x + 1)] + 1/2


multiplying by LCD [2x(x+1)] ___ 240x + 240 = 240x + x^2 + x


0 = x^2 + x - 240


factoring ___ 0 = (x + 16)(x - 15)


x + 16 = 0 ___ x = -16 ___ negative value not realistic


x - 15 = 0 ___ x = 15