so first add them up
1/2+1/10
convert 1/2 with denomenator of 10
1/2 times 5/5=5/10
5/10+1/10=6/10=3/5
he traveled 3/5 hours
4 miles
4 miles per 3/5 hours
average speed is miles per 1 hour
4 miles =3/5 hours
multly both sides by 5/3 to meake 3/5 equal 1 (3/5 times 5/3=15/15=1)
20/3=1 hour
6 and 2/3=1 hour
6 and 2/3 miles per hour is speed