Anita's speed is four miles per hour. Brother leaves 12 min after catches up 24 min after. Both constant running speed. What is brother miles per hour.

Question

Both have constant jogging speed.  Brother leaves 13 min after sis. Sis 4 miles per hour. Brother catches up after 24 minutes.

Answer 1

Anita runs 12+24 = 36 min = 36/60 hr = 3/5 hr 

Since her speed is 4 mph, she runs 4(3/5) = 12/5 miles = 2 and 2/5 miles

 

The brother runs the same 12/5 miles in 24 min = 24/60 hr = 2/5 hr

12/5 divided by 2/5 = 12/5 * 5/2 = 6 mph