There are 40 cats in the ecosystem.
You set 1/5 equal to x/200. Then you cross multiply the fractions to get 5x=200. You divide both terms by 5 to get x, which equals 40.
Answer:
Step-by-step explanation:
If you look at the numbers you are given, you see that the first purchase has 3 more adult tickets than the second purchase, and its cost is £24 more. This means an adult ticket costs £24/3 = £8.
Two adult tickets will cost 2×£8 = £16, so three child tickets cost ...
£31 -16 = £15
Each child ticket is then £15/3 = £5.
An adult ticket costs £8; a child ticket costs £5.
Let x be ml of 5% soln.
let 500-x be ml of 25% soln.
.
x*.05=.05x
(500-x)*.25=125-.25x
500*.20=100
.
.05x+125-.25x=100
-.2x=-25
x=-25/-.2
x=125 ml of 5% soln.
500-x=375 ml of 25% soln.
.
Check:
125*.05= 6.25
375*.25=93.75
---------------
========100
Answer:
Option B. 
Step-by-step explanation:
we know that
The area of a circle is equal to

we have

substitute

Remember that
radians subtends the complete circle of area 
so
by proportion
Find the area of the related sector for a central angle of
radians
Let
x------> the area of the related sector

The answer is 640 because if you multiply the total student of 6h grade by 100 and divide by 30. You will get the total of student in the school