Answer:
4) C
5) C
Step-by-step explanation:
There would be 35 rulers.
In order to solve this, use cross multiplication.
6/10 = 21/x -----> cross multiply
10*21 = 6*x
210 = 6x
35 = x
Answer:
x =
, y = 
Step-by-step explanation:
1. Isolate for x in one of the equations:
2x = 9x - 14y
2x-9x = 9x-9x -14y
-7x = -14y
-7x/-7 = -14y/-7
x = 2y
2. Substitute 2y in for x in the second equation:
9(2y) = 40 - 14y
3. Simplify:
18y = 40 - 14y
4. Isolate for y:
18y+14y = 40 -14y+14y
32y = 40
32y/32 = 40/32
y = 
5. Substitute the new y-value into the simplified expression x = 2y:
x = 2(5/4)
x = 
hope this helps!
Check picture below, radius = r = 15, thus