Question

this graph shows the number of times dani’s heart beats during a minute, while watching tv.
what does the initial value and the rate of change mean in this situation?
select an answer
a dani starts her count at 0 heartbeats and her heart beats 15 times every second.
b dani starts her count at 0 heartbeats and her heart beats 1.5 times every second.
c dani starts her count at 0 heartbeats and her heart beats 1 time every second.
d dani starts her count at 0 heartbeats and her heart beats 10 times every second.

Explanation:

Step1: Find initial value

Initial value is at time=0: 0 heartbeats.

Step2: Calculate rate of change

Rate = $\frac{\Delta \text{heartbeats}}{\Delta \text{time}}$. Take two points: (10,10) and (20,20). Rate = $\frac{20-10}{20-10}=1$ per second.

Answer:

C. Dani starts her count at 0 heartbeats and her heart beats 1 time every second.