what is his average jogging speed?

Question

3. James can jog twice as fast as he can walk. He was able to jog the first 9 miles to his grandmother’s house, but then he tired and walked the remaining 1.5 miles. If the total trip took 2 hours, then what was his average jogging speed?

Answer 1

2(j + j/2) = 10.5

3j/2 = 21

3j = 42

j = 14 mph