Answer:
12 books
Step-by-step explanation:
30 multiply by 2/5=12 books that were sold to co-workers.
3/5 which is the remainder multiplied by 1/2 =3/10
3/10 multiply by 30 =6 books sold to her neighbours
now that 30 is the original subtract12 +6
Answer
Find out the original side length of the square .
To prove
Let us assume that the original length of the square be x.
Formula

As given
The dimensions of a square are altered so that 8 inches is added to one side while 3 inches is subtracted from the other.
Length becomes = x + 8
Breadth becomes = x -3
The area of the resulting rectangle is 126 in²
Put in the formula
(x + 8) × (x - 3) = 126
x² -3x + 8x -24 = 126
x ²+ 5x = 126 +24
x² + 5x - 150 = 0
x² + 15x - 10x - 150 = 0
x (x + 15) -10 (x +15) =0
(x + 15)(x -10) =0
Thus
x = -15 , 10
As x = -15 (Neglected this value because the side of the square cannot be negative.)
Therefore x = 10 inches be the original side of the square.
V = pi * r^2 *h
where r is the radius and h is the height of the cylinder
V = pi * 7^2 *4
V = pi* 49*4
pi is approximated by 3.14 or 22/7
V = 22/7 * 49 * 4
V = 616 units ^3
The answer would be 12.599
According to the Pythagorean theorem, the square of the hypotenuse (the longest side) of a right-angled triangle equals to the sum of the squares of the other two sides. In this case, the ladder is the hypotenuse, which equals to the distance between the bottom of the ladder and the tree + the distance we want to find (x):
5² + x² = 13²
25 + x² = 169
x² = 144
x = √144 = 12.
The distance between the ground and the top of the ladder is 12 ft.