Question 167940
Let {{{r}}}= the plane usual speed in km/hr
Let {{{t}}}= the usual time to make the trip in hours
{{{d = r*t}}}
It is given that
{{{d = 4400}}} km
{{{4400 = r*t}}}
{{{t = 4400/r}}}
Also given is
{{{4400 = (r + .1r)*( t - .5)}}}
{{{4400 = 1.1r*(4400/r - .5)}}}
{{{4400 = 4840 - .55r}}}
{{{.55r = 440}}}
{{{r = 800}}}
and
{{{t = 4400/r}}}
{{{t = 4400/800}}}
{{{t = 5.5}}}
The plane usually flies at 800 km/hr
check:
{{{4400 = (r + .1r)*( t - .5)}}}
{{{4400 = (800 + .1*800)*( 5.5 - .5)}}}
{{{4400 = 880 * 5}}}
{{{4400 = 4400}}}
OK