Hello!

We can go through each answer to verify whether each is equivalent to 8 : 6.
4 : 3 is equivalent to 8 : 6 because reducing the ratio 8 : 6 by a factor of 2 yields 4 : 3.
6 : 8 is not equivalent to 8 : 6 because the ratio is reversed.
16 : 12 is equivalent to 8 : 6 because the ratio is increased by a factor of 2.
10 : 8 is not equivalent to 8 : 6. We can verify this by checking whether each term was scaled equally:
10 ÷ 8 = 1.25
8 ÷ 6 = 1.33. Therefore, they are unequal.
7 : 5 is not equal to 8 : 6 for the same reason.
The only correct choices are:
4 : 3 and 16 : 12.
Given:
The increase in pressure P is the linear function of the depth d.

The cost of dinner is $300 and $10 per students.
To find:
The initial value and rate of change and their interpretation.
Find the cost function C where n is the number of students.
Solution:
The slope intercept form of a linear function is
...(i)
where, m is rate of change and b is y-intercept or initial value.
We have,
...(ii)
From (i) and (ii), we get

The initial value is 14.7. It means, the pressure at sea level is 14.7 pounds psi.
Rate of change is 0.445. It means, the pressure is increasing by 0.445 pounds psi for every feet.
The cost of dinner is $300 and $10 per students.
Let C(n) be the total cost for dinner and n be the number of students.
Fixed cost = $300
Additional cost for 1 student = $10
Additional cost for n student = $10n
Now,
Total cost = Fixed cost + Additional cost

Therefore, the required cost function is
.
(-2x+4)+2(2x+1)= -2(-x-3)
In fact, this problem belongs to the chemistry section. Recall that many other sciences require mathematical calculations. The problem will belong to Mathematics only if no knowledge of other sciences are required to solve the problem.
Solubility for the given substances is measured in grams per 100 g of water at a particular temperature (20 deg.C).
This means that the mass (assumed to be the solute) will not change the solubility, just the minimum quantity of solvent (water) will.
Thus the solubility of sodium chloride will remain L=36 g/100g H2O for any quantity of solute. Similarly, the solubility of lead nitrate will remain as K=54 g/100 g H2O.
The reason that they remain constant is because the quantity of solvent (water) is fixed at 100 g. Varying amount of solute will affect the quantity of solvent required, but not the solubility.
I'll leave it to you to calculate the difference between K & L.