Question

Mr Nersin likes to ride his bike. He rode for 1/2 hour. After a short rest, he rode 1/10 hour more. He traveled 4 miles in all. What is his average speed?

Answer 1

The distance traveled by Mr.Nersin = 4 miles
The time for which Mr.Nersin rode first = 1/2 hour
The time for which Mr.Nersin rode after a short rest = 1/10 hour
Then
The total time for which Mr.Nersin rode = (1/2) + (1/10) hour
                                                                = (5 + 1)/10 hour
                                                                = 6/10 hour
                                                                = 3/5 hour
So
Average speed of Mr. Nersin = Distance traveled / Time taken
                                                = 4/(3/5) miles/hour
                                                = (4 * 5)/3 miles/hour
                                               = 20/3 miles/hour
                                                = 6 2/3 miles/hour
                                                = 6.67 miles per hour
So the average speed at which Mr.Nersin traveled is 6 2/3 or 6.67 miles per hour.

Answer 2

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