John can jog twice as fast as he can walk. He was able to jog the first 5 miles to his grandmother's house, but then he tired and walked the remaining 2 miles. If the total trip took 0.9 hours, then what was his average jogging speed?

Step 1 ：We know that John jogged 5 miles and walked 2 miles. We also know that his jogging speed is twice his walking speed. We can use the formula for speed, which is distance divided by time, to set up an equation to solve for his jogging speed. We know that the total time for the trip was 0.9 hours, so we can set up the equation as follows:

Step 2 ：\(\frac{5}{\text{jogging speed}} + \frac{2}{\text{jogging speed}/2} = 0.9\)

Step 3 ：We can solve this equation for jogging_speed to find John's average jogging speed.

Step 4 ：\(\text{jogging speed} = 10.0000000000000\)

Step 5 ：Final Answer: John's average jogging speed was \(\boxed{10}\) miles per hour.