15. edgar anderson earns $200 a week plus a 15% commission on all sales over $1,000. if mr. anderson's sales for one week are $2,500, what is his gross pay for that week?
a. $350
b. $525
c. $575
d. $425

16. which one of the following statements expresses a true proportion?
a. 14 : 6 = 28 : 18
b. 42 : 7 = 6 : 2
c. 2 : 3 = 3 : 2
d. 3 : 5 = 12 : 20

15. 

2500 X 15 = 37500
37500 ÷ 100 = 375
375 + 200 = 575
The answer is C.

16. 
The easiest way to answer this question is by going through each answer one by one: 

14:6 = 28:18
28 ÷ 14 = 2
18 ÷ 6 = 3
Since both numbers were multiplied by different numbers, we can establish that this is not a true proportion. 

42:7 = 6:2 
42 ÷ 7 = 6
7 ÷ 7 = 1
42:7 = 6:1
By dividing both numbers by the same number, we can establish that the answer is wrong. 

2:3 = 3:2
This is obviously wrong. That is because, in ratios, the order counts. So the first 3 is more than the first 2, therefore the second number on the other side of the ratio should be more than the first. 

3:5 = 12:20
12 ÷ 3 = 4
20 ÷ 5 = 4
Since both numbers were multiplied by the same number, this is a true proportion. 

The answer is D.