Y=(kx)/z
15=(k10)/4
15=(5k/2)
15=k(5/2)
ties both sides by 2/5 to clear fraction
6=k
y=(6x)/z
x=20
z=6
y=(6*20)/6
y=20
Solution
The range is defined as:
Range = Max - Min
For this case we can conclude that the best solution would be:
B, C
1. 1/9 since you take all the "a"s in the words which is 2/18
2.2/9 same thing as above
3.18/18 since there is no "O" it's a trick question
4.3/9
5.5/6 since you don't count 6
6.1/2 and 1/2 coins are always 1/2 unless you flip twice
7.5/13
8.1/2 because 1,3,5 odd 2,4,6 even
Hope that helps
10)

11)

12)

13) (your answer is incorrect)

14) (your answer is incorrect)

15)

16)
-expression to represent this situation

Answer: In 1 group 57 students
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P.S. Hello from Russia :^)