Step-by-step explanation:
If a variables varies jointly, we can just divide it by the other variables in relation to it.
For example, since p variables jointly as q and square of r, then

where k is a constant
First, let find k. Substitute p= 200
q= 2, and r=3.



Now, since we know our constant, let find p.

Q is 5, and r is 2.



Answer:
74 hope this works if not I'm sorry
Answer:
x = 9
y = 9
Step-by-step explanation:
Given :
Let :
Kenyan French roast coffee = x
Cost per x = $8
Sumatran Coffee = y
Cost per y = $10
x + y = 18 - - - - (1)
8x + 10y = 9 * 18 ;
8x + 10y = 162 - - - - (2)
From (1):
x = 18 - y
Put x = 18 - y in (2)
8(18 - y) + 10y = 162
144 - 8y + 10y = 162
2y = 162 - 144
2y = 18
y = 9
x = 18 - y
x = 18 - 9
x = 9