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

yes because they have the same amount of green and blur marbles.

step-by-step explanation:

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: