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:
The value of x = 3.42
Step-by-step explanation:
Formula:
Sin ∅ = Opposite side /Hypotenuse
From the figure we can see a right angled triangle.
One angle is given, hypotenuse = 10 and height = x.
To find the value of x
sin 20 = Opposite side/hypotenuse = x/10
x = 10 * sin 20
= 10 * 0.342 = 3.42
Therefore the value of x = 3.42
Answer:
5 students
Step-by-step explanation:
.............,
Answer: The value of x is 40.25
Answer:
Region C
Step-by-step explanation:
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