Help me please ! i’ll mark brain list and double the points .
2 answers:
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Answer:
80 m^2
Step-by-step explanation:
The given information lets you write two equations involving length (x) and width (y).
- 2(x +y) = 36 . . . . the perimeter is 36 m
- (x+1)(y+2) -xy = 30 . . . . increasing the length and width increases area
The second of these equations simplifies to another linear equation, giving a system of linear equations easily solved.
xy +y +2x + 2 -xy = 30
2x +y = 28 . . . . . . . subtract 2
Dividing the first equation by 2 gives
x +y = 18
and subtracting this from the above equation gives ...
(2x +y) -(x +y) = 28 -18
x = 10
Then
y = 18 -10 = 8
The area of the original rectangle is xy = 10·8 = 80 m^2.
Answer:
b) 24
Step-by-step explanation:
We solve building the Venn's diagram of these sets.
We have that n(S) is the number of succesful students in a classroom.
n(F) is the number of freshmen student in that classroom.
We have that:
In which n(s) are those who are succeful but not freshmen and are those who are succesful and freshmen.
By the same logic, we also have that:
The union is:
In which
So
So the correct answer is:
b) 24