Answer:
12
Step-by-step explanation:
This is a joint variation problem:
z varies directly as x and y
Interpreting this;
z ∝ xy
Therefore;
z = kxy
z = 6, x = 2, y = 6
Now find k,
6 = 2 x 6 x k
6 = 12k
k =
To find the value of z;
x = 3, y = 8
z =
x 3 x 8 = 12
Answer:
The answer is 
Step-by-step explanation:
Assuming the snowball is a perfect sphere, then if A denotes the surface area and D the diameter then:

Differentiating wrt r we have:

We are told that
and we want to find 
By the chain rule we have:

∴
∴
When D=10 then

The sign (-) shows that the D is decreasing.
Make a proportion:

Then cross multiply and divide to solve.
20x=119
x=5.95
The answer is $5.95
Y is increased by 6 because if you imagine x being 3 then y would = 16 but if you increase x by 3 making 6 then y would = 22 and 16 increased by 6 is 22
168,356. the ten thousand is the 6. To find the estimate, the one would stay there and the six would become a seven because the eight eight before the six is above five. All in all, the answer is 170.000