Question 373857
Both planes have traveled the same distance when they meet
which is 1680 mi
given:
1st plane:
{{{d = r*t}}}
(1) {{{1680 = 420*t}}}
2nd plane:
{{{1680 = r*(t -.5)}}}
(2) {{{1680 = r*t - .5r}}}
From (1):
{{{t = 1680/420}}}
{{{t = 4}}}
(2) {{{1680 = 4r - .5r}}}
{{{r*(4 - .5) = 1680}}}
{{{r = (2/7)*1680}}}
{{{r = 480}}}
The 2nd plane's rate is 480 mi/hr