The answer to your question is b
Answer:
13
Step-by-step explanation:
25 - 12 = 13
Answer:
Step-by-step explanation:
Suppose that the side length is s. Imagine that one side is level. Draw a vertical line through the top vertex perpendicular to the base (level side). Label this vertical line "h." Then h and s are related as follows:
√3 h
sin 60 degrees = ------- = --------
2 s
s√3
and so h = the height of the triangle = -----------
2
The area of this triangle is (1/2)(base)(height), which here is:
(1/2)(s/2)( s√3 /2), or
(s^2)√3
A = ---------------
8
from what I know
A=4
B=3
C=2
and a plus adds 0.33 and a minus minuses 0.33
question wants us to find yearly average or average per 1 year
since these grades span over 2 years, we must divide the total average by 2
averagefresh=sum of fresh grades/4 grades per year
averagesoph=sum of soph grades/4 grades per year
yearlyaverage=(averagefresh+averagesoph)/2
freshman:
(C)+(B)+(A)+(C-)=2+3+4+(2-0.33)=10.67
sophomore:
(B+)+(A-)+(C+)+(B-)=(3+0.33)+(4-0.33)+(2+0.33)+(3-0.33)=12
averagefresh=10.67/4=2.6675
averagesoph=12/4=3
yearlyaverage=(2.6675+3)/2=2.83375
so it's about a 
average
Let C = the Chinese books.
Let E = the English language books.
C = 4/5 E
E - 300 = C - 180 Notice how you get this equation. You take 300 away from the English books and 180 from the Chinese and according to the question, you get an equal number of both. Put c = 4/5E into the second equation.
E - 300 = 4/5 E - 180 Add 300 to both sides.
E = 4/5 E - 180 + 300
E = 4/5 E + 120 Now subtract 4/5 E from both sidies.
E - 4/5 E = 120
1/5 E = 120 Now multiply by 5
E = 120 * 5
E = 600
So the number of books are
600 written in English
4/5 of 600 = 2400 /5 = 480 Chinese books.
English 600
Chinese 480
