Ken's average driving speed is 25km/hr faster than Jim's. In the same length of time it takes Ken to drive 279 km, Jim drives only 204 km. What is Ken's average speed?

Possible Answers:

a) 93 km/hr
b) 118 km/hr
c) 43 km/hr
d) 68 km/hr

Let x equal the speed of Jim's car.

279/x + 25 = 204/x
204x + 5100 = 279x
5100 = 75x
5100/75 = 75/75x
x = 68km/h

Therefore the avg. speed of Jim's car is 68km/h. Since Ken's car is 25km/h faster...68+25 = 93km/h.
Therefore the avg. speed of Ken's car is 93 km/h.

To solve this question, we can set up a equation using the information given.

Let's assume that Jim's average speed is x km/hr. According to the question, Ken's average speed is 25 km/hr faster than Jim's. Therefore, Ken's speed is x + 25 km/hr.

Next, we know that both Ken and Jim take the same amount of time to drive their respective distances. So, we can set up the equation:

Distance/Speed = Time

For Jim:
204 km / x km/hr = Time

For Ken:
279 km / (x + 25) km/hr = Time

Since the time taken is the same for both, we can equate the two equations:

204/x = 279/(x + 25)

To continue solving, we can cross-multiply:

204(x + 25) = 279x

Expanding the equation:
204x + 5100 = 279x

To isolate the variable, we can subtract 204x from both sides:
5100 = 279x - 204x

Combining like terms:
5100 = 75x

Finally, to solve for x, we can divide both sides by 75:
x = 5100/75

Simplifying the division:
x = 68 km/hr

Therefore, Jim's average speed is 68 km/hr.

Since Ken's speed is 25 km/hr faster, Ken's average speed is 68 + 25 = 93 km/hr.

Hence, the correct answer is a) 93 km/hr.