Answer:
Option A is correct.
The constant of variation is, 
Step-by-step explanation:
The Direct variation says that:
if a vary directly to b then, the equation is of the form: a = kb where k is the constant of variation.
Given: if y varies directly as x.
By definition of direct Variation:
y = kx where is the constant of variation.
It is also given that: y = -3 and x =2
Solve for k;
-3 = 2k
Divide both sides by 2 we have;

Therefore, the constant of variation is, 
1m= 1000mm
so 64mm*1m/1000mm=64/1000m
Answer:
768
Step-by-step explanation:
Given that:
Error margin (E) = 5% = 0.05
Confidence level = 95%
Proportion p = 0.5 (since no prior value is given) ; also n1 = n2 = sample size
n = (Z / E)^2 * (1 - p)
1 - p = 1 - 0.5 = 0.5
Zscore at 95% confidence = 1.96
n = (1.96 / 0.05)^2 * 0.5
n = 39.2^2 * 0.5
n = 1536.64 * 0.5
n = 768.32
Hence, sample size = 768 SAMPLES
Answer:
<h2>
9x - 13</h2>
Solution,
f(X)= 2x-1
g(X)= 7x-12
Now,

Hope this helps...
Good luck on your assignment...
N*(21/100)=(700/100)
n=(700/100)/(21/100)
n=(700/100)*(100/21)
n=700/21
n=33+1/3
So <em><u>thirty three</u></em> $0.21 pencils can be purchased for $7.00.