When the concentration of a solution is expressed in weight percentages, that is just equal to the mass of solute over the mass of the total solution. For a solution weighing 210 grams, 5% of it is salt. That is equal to
210*0.05= 10.5 g salt
The rest of the amount, determined by difference, is the amount of solvent which is water.
water = 210-10.5 = 199.5 g salt
To solve for the new concentration, you add up 15 g to the already existing 10.5 g of salt in the solution. The water, on the other hand, remains constant.
Concentration = (15+10.5)/(210+15) = 0.1133 or 11.33%
Answer:
6 ways
Step-by-step explanation:
Given
Number of Sports: 3
Required
Determine the total number of schedules
Since, there are 3 sports and the schedule is in no particular order.
The number of schedules is calculated as thus:

Where:

So, we have:


Find the z-scores for the two scores in the given interval.

For the score x =391,

.
For the score x = 486,

Now you want the area (proportion of data) under the normal distribution from z = -1 to z = 0. The Empirical Rule says that 68% of the data falls between z = -1 to z = 1. But the curve is symmetrical around the vertical axis at z = 0, so the answer you want is HALF of 68%.