Question

for exercises 61-64, use th
human heart rates
age
(years)
beats per
minute
newborn
140
1
120
6
100
10
90
12
85
adult
80

1. how

adults he

1. in h

newborns

1. in how many seconds

will a 12-year-olds heart
beat 17 times.

Explanation:

Step1: Determine the heart rate of a 12-year-old.

From the table, a 12-year-old's heart rate is 85 beats per minute.

Step2: Set up a proportion to find time in seconds.

Let \( t \) be the time in seconds. We know that 85 beats occur in 60 seconds (1 minute), so we set up the proportion:
\[
\frac{85 \text{ beats}}{60 \text{ seconds}} = \frac{17 \text{ beats}}{t \text{ seconds}}
\]
Cross - multiply: \( 85t=17\times60 \)

Step3: Solve for \( t \).

First, calculate \( 17\times60 = 1020 \). Then, \( t=\frac{1020}{85} \)
\( t = 12 \)

Answer:

12