John entered a cross-country ski race. The first part of the race was 15 km long, and he completed it in 1 hour. The second part was 18 km long, and he completed this part in an hour and a half. What was John's average speed for the whole race? A. 28 kilometers per hour B. 27 kilometers per hour C. 13.6 kilometers per hour D. 13.2 kilometers per hour

option D is the correct answer.

Step-by-step explanation:

The first part of the race was 15 km long, and he completed it in 1 hour.

Speed = distance/time

Therefore, John's speed in the first part of the race would be

15/1 = 15km/hr

The second part was 18 km long, and he completed this part in an hour and a half. This means that his speed in the second part of the race is

18/1.5 = 12km/hr

Total distance/total time

Total distance for both parts of the race is 15 + 18 = 33km

Total time for the race is 1 + 1.5 = 2.5 hours

John's average speed for the whole race would be

33/2.5 = 13.2 kilometers per hour

probability for j is 1/4

while

a is 1/6

it is 10.6 according to my calculations