Answer:
[tex]\huge\fbox{Answer ☘}[/tex]
[tex]\bold\blue{190 \:miles/hr \:and \:170 \:miles/hr}[/tex]
Step-by-step explanation:
Let the speed of faster plane be x
therefore ,
speed of slower plane = x - 20
As the time taken is same ,
[tex] \frac{285}{x} = \frac{255}{x - 20} \\ \\ \frac{57}{x} = \frac{51}{x - 20} \\ \\ 57(x - 20) = 51x \\ \\ 6x = 1140 \\ \\ x = 190[/tex]
therefore ,
faster plane travels at a speed of 190 miles/hr
while..
the slower plane travels at a speed = ( 190-20 ) miles/hr
=> 170 miles/hr
hope helpful~