Inge is competing in a 400 m race. She runs at a constant speed of 4.6 m/s for the first 150 m, then 4.2 m/s for 40 seconds. The remainder of the race takes her 38 seconds to complete. What is Inge's average speed for the entire race to 1 dp?

9514 1404 393

  3.6 m/s

Step-by-step explanation:

To find Inge's average speed for the race, we need to know her total distance (400 m) and her total time. The times for the 2nd and 3rd portions of the race are given, but we need to figure the time for the first portion. That will be ...

  time = distance/speed

  time = (150 m)/(4.6 m/s) = 32.609 s . . . . time for first 150 m

Then Inge's average speed is ...

  (400 m)/(32.609 s + 40 s + 38 s) = (400 m)/(110.609 s) ≈ 3.6 m/s

4 puzzles in 3 hours

step-by-step explanation:

lockers 1, 4, 9, 16, 25, 40, and 49 are open

i ran through it by the other answer is wrong