Question

for train a, if the average speed on saturday is 20% more than that on wednesday and the mean of the average speeds over all the six days is 67 km/hour then what is the average speed on saturday?

Answer 1

The average speed of train A on Saturday is approximately 77.81 km/h when Wednesday's speed is increased by 20%.

Step-by-step explanation:

To find the average speed of train A on Saturday, we can use the information that the mean average speed over six days is 67 km/h. Since Saturday's speed is 20% higher than Wednesday's, let's denote Wednesday's average speed as w.

First, we calculate 20% of w:

• 0.20 × w

Which gives us the average speed for Saturday:

• w + 0.20 × w = 1.20 × w

To find the average speed over six days (including Saturday's 1.20 × w), we have:

6 × 67 km/h = sum of speeds for all six days

If 'w' is the average speed for all days other than Saturday, the equation becomes:

1. (5 × w) + (1.20 × w) = 6 × 67
2. 6.20 × w = 402
3. w = 402 / 6.20
4. w ≈ 64.84 km/h (Wednesday's average speed)

Finally, we calculate Saturday's speed:

• 1.20 × 64.84 km/h ≈ 77.81 km/h