(NEED HELP WITH NUMBER 1!!!)
1 answer:
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Answer:
<em>Cathy was born in 1980 and she was 18 years old in 1998</em>
Step-by-step explanation:
<u>Equations</u>
This is a special type of equations where all the unknowns must be integers and limited to a range [0,9] because they are the digits of a number.
Let's say Cathy was born in the year x formed by the ordered digits abcd. A number expressed by its digits can be calculated as
In 1998, Cathy's age was
And it must be equal to the sum of the four digits
Rearranging
We are sure a=1, b=9 because Cathy's age is limited to having been born in the same century and millennium. Thus
Operating
If now we try some values for c we notice there is only one possible valid combination, since c and d must be integers in the range [0,9]
c=8, d=0
Thus, Cathy was born in 1980 and she was 18 years old in 1998. Note that 1+9+8+0=18
Answer:
A = 153.94 sq mi
Step-by-step explanation:
In this scenario, we would be starting from the center point and searching the area of a square since the distance in every direction would the same 7 mi. This 7-mile distance would be our radius in this scenario. We now need to use the formula for the Area of a circle to calculate the search area. This formula is the following
A =
A =
A =
A = 153.94 sq mi
A total of 153.94 square miles must be searched.