Question

carol and juan were playing with carols new train set. they pushed the trains around the track. they tried four different sections of track. which statement is true? a the train on track 3 was slower than the train on track 1. b the train on track 1 was faster than the train on track 2. c the trains on tracks 1, 2 and 3 all had the same average speed. d the train on track 2 was slower than the train on track 4. track length (cm) travel time (s) 1 20 2 2 20 2 3 60 6 4 40 6

Explanation:

Step1: Calculate speed for each track

Speed formula is $v=\frac{d}{t}$, where $d$ is distance and $t$ is time.
For Track 1: $v_1=\frac{20}{2}=10$ cm/s.
For Track 2: $v_2=\frac{20}{2}=10$ cm/s.
For Track 3: $v_3=\frac{60}{6}=10$ cm/s.
For Track 4: $v_4=\frac{40}{6}=\frac{20}{3}\approx6.67$ cm/s.

Step2: Analyze each option

• Option A: The train on Track 3 ($v_3 = 10$ cm/s) was not slower than the train on Track 1 ($v_1=10$ cm/s), so this is false.
• Option B: The train on Track 1 ($v_1 = 10$ cm/s) was not faster than the train on Track 2 ($v_2 = 10$ cm/s), so this is false.
• Option C: The trains on Tracks 1, 2 and 3 all have a speed of 10 cm/s, so they have the same average speed. This is true.
• Option D: The train on Track 2 ($v_2=10$ cm/s) was faster than the train on Track 4 ($v_4\approx6.67$ cm/s), so this is false.

Answer:

C. The trains on Tracks 1, 2 and 3 all had the same average speed.