Question

A human chain is formed by 60 people standing with their arms outstretched, each holding the hand of the person on either side. The first 30 people in the chain have arm spans of 6 feet. The next 30 people have arm spans of 5.5 feet. At the word "go!" the first person squeezes the hand of the second person. Then the second person squeezes the hand of the third, and so on. Assume that each person takes 1/3 second to pass along the signal. Which piecewise function correctly models the distance that the signal travels in t seconds?

Answer 1

Here's the real answer.

for T=0 to T=10, D = T*3*6
for T>10 to T=20, D = 30*6 + (T-30)*3*5.5

The signal travels faster in the first half, 18 feet per second vs 16.5 feet per second

Answer 2

So would that be the last answer on the picture?