Answer:
t
Step-by-step explanation:
Label the books returned "b", and the books sold on monday "m", and the books sold on tuesday "t", and the books returned "r".
the formula:

(you can remove the brackets)
Answer:
Population 120 given the survey, sample 90 who answered the survey.
Step-by-step explanation:
The entire amount of employees who even received the surveys at all was 120. Because the total number was 120, 120 is the population.
Only 90 out of 120 surveys were received, so 90 is the sample because it is part of 120.
Hope this helps :)
Answer:
60 students passed, and 75 appeared in examination.
Step-by-step explanation:
Let's say s is the total number of students and p is the number of students who passed.
80% of the students passed, so:
0.8 s = p
If there were 10 less passers, and 15 less students (5 less failures), then the ratio of passers to failures would be 5/1.
(p − 10) / (s − p − 5) = 5 / 1
Simplify the second equation:
p − 10 = 5 (s − p − 5)
p − 10 = 5s − 5p − 25
6p = 5s − 15
Substitute the first equation.
6 (0.8 s) = 5s − 15
4.8 s = 5s − 15
0.2 s = 15
s = 75
p = 0.8 s
p = 60
60 students passed, and 75 appeared in examination.
Answer:
y=x+1
or x=y-1
Step-by-step explanation:
X= 70 degrees
Y= 70 degrees
Understand that every triangle has three angles and they add up to 180 degrees.
If I split this triangle in half the total degrees of each individual piece will be 90 degrees. A split in the isosceles triangle will also cause the 40 degrees to halved (thus, how I got 20 degrees in our 90 triangle).
Since we are dealing with an isosceles triangles two of the sides will be equal (hence, the dashes on the triangles sides). Therefore, x and y will also be equal.
Now if our 40 degreed angle is now 20 degrees, we have an unknown angle and the triangle in total now adds up to 90 degrees we can set up an equation.
20 + y = 90
Y = 70
Since X and Y are equal, X will also be 70.
If we return to to the isosceles triangle before it was split (use your photo for reference) and we add 40 +70 + 70 we will get 180 degrees. Which is the standard total of degrees for any triangle that is not a 90 degreed triangle.
I hope this helps. Feel free to ask questions.
Below I uploaded my work.