A * * * ran 13 points, deducted 10 points, and A ran for three hours; B ran for two hours and forty minutes.

X hours later, B caught up with A, 8x =10x-(1/3 *10) 2x =10/3x = 5/3 hours = 100 minutes.

8 * 5/3 =10 * 4/3 = 40/3km

40/3km+9 * 5/60 = 40/3+3/4 = (40 * 4+3 * 3)/12 =169/12km This is a journey, a journey forward.

The time is 105 minutes, one *** 180 minutes, and there are still 75 minutes, which is 5/4 hours.

At what speed did you finally run back?

( 169/ 12)/(5/4) = ( 169/ 12) * (4/5) = 169/ 15 = 165438