Answer:
Step-by-step explanation:
The change represents the decay
The percentage rate of decrease is 6.2%
Step-by-step explanation:
The formula of the exponential growth is y = a , where
a is the initial value
r is the rate of increase in decimal ⇒ (1 + r) > 1
The formula of the exponential decay is y = a , where
a is the initial value
r is the rate of decrease in decimal ⇒ (1 - r) < 1
Let us solve the question.
∵ y = 91
→ Compare it with the forms above
∴ a = 91
∵ The rate of change is 0.938
∵ 0.938 < 1
→ That means the rate of change is decreasing
∴ The function y = 91 represents exponential decay
∴ The change represents the decay
→ From the 2nd form above
∵ (1 - r ) = 0.938
→ Subtract 1 from both sides
∴ 1 - 1 - r = 0.938 - 1
∴ - r = - 0.062
→ Divide both sides by -1
∴ r = 0.062
→ Multiply it by 100% to change it to a percentage
∵ 0.062 × 100% = 6.2%
∴ r = 6.2%
∴ The percentage of decrease is 6.2%
