Respuesta :

s1m1
At rate x miles/ hour drove d miles/ 4 hours;
At rate x-10 miles / hour drove d miles/5 h

d miles = x• 4 miles first rate
d miles= (x-10)•5 miles second rate

5x-50= 4x
5x-4x= 50
X= 50 miles/h to get to the beach
50-10= 40 miles/h to get home