Answer:
70/9
Step-by-step explanation:
9x-81= -11
9x=-11+81
9x= 70
x= 70/9
we know that
The simple interest formula is equal to

where
A is the Final Investment Value
P is the Principal amount of money to be invested
r is the rate of interest
t is Number of Time Periods
in this problem we have

substitute in the formula above

solve for r



therefore
<u>the answer is</u>
the rate of interest is 
Answer:
A. 40 mph
Step-by-step explanation:
A bird flies 2/3 miles per minute. You are trying to solve miles per hour.
Note that there are 60 minutes in an hour. Multiply 2/3 with 60:
2/3 x 60 = (2 * 60)/3 = (120)/3 = 40
A. 40 mph is your answer.
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