Answer:
The rate of decrease is 8%
Step-by-step explanation:
we know that
The general equation for the radioactive decay can be written as:

where
a is the amount in kilograms after time t.
a_0 is the original amount of the substance or y-intercept of the function
r is the decay rate, written in decimals.
t is the time
In this problem we have

so

solve for r

Convert to percentage

The answer is in the photo.
For this problem, you will have to use PEMDAS (Parentheses) (Exponents) (Multiplication/Division) (Addition/Subtraction)
First of all, you will want to solve for the values inside the parentheses first
40 <span>÷ 1+3-(21)+7-5 Now check for anything that includes multiplication/division and do that
40+3-21+7-5 All you have left now is addition and subtraction. It must go from left to right, therefore if addition is first, do addition, if subtraction is first, then do subtraction.
Final answer = 24</span>
Answer:
24 picture frames
Step-by-step explanation:
Since a student takes 1/6 hour to paint a picture frame, so in an hour, the student will paint a total of 6 picture frames. So to find the number of picture frames in 4 hours, you just need to multiply 4*6 to get 24 picture frames.