The diagram below shows the percentage of their total sleep that men and women spend in deep sleep, depending on their age in years, A - Junior Cycle Mathematics - Question 3 - 2021

Gina sleeps an average of 8 hours each night. To find the total sleep per week, we calculate:

$8 ext{ hours/night} \times 7 \text{ nights} = 56 \text{ hours/week}$.

Since Gina spends approximately 15% of her total sleep in deep sleep, we find:

$56 \times 0.15 = 8.4 \text{ hours/week}$.

Thus, Gina spends about 8.4 hours in deep sleep each week.

From the diagram, it appears that women spend a lower percentage of their deep sleep than men from ages 12 to 40. Thus, the inequality can be filled as:

$12 < A < 40$.

6 billion can be expressed in scientific notation as:

$6 \times 10^9$.

To complete the table, we can see that there is a linear decrease in the percentage of total sleep spent in deep sleep. To find the missing values, we can observe the pattern:

• Percentage at 40 years is 15.0.
• Percentage at 45 years is 13.6.
• The decrease appears to be 1.4 for each 5-year increment.
• Therefore:
  • For 50 years, the percentage will be approximately 12.2.
  • For 60 years, the percentage continues at 12.2.

Thus, we complete the table with:

The slope of -0.14 indicates that for each additional year of age, the percentage of total sleep spent in deep sleep decreases by 0.14%. This means that as men age, they tend to spend less time in deep sleep on average, highlighting a gradual decline in deep sleep percentage with advancing age.