9514 1404 393
Answer:
(C) no solutions
Step-by-step explanation:
If you multiply the first equation by 2, you get ...
2x +2y = 4
When you compare this to the second equation ...
2x +2y = 8
you realize there are <em>no values of x and y that can satisfy both equations</em>. There are no solutions.
The original price is @42. To check, find 10% of $42, which is $4.2. Now just subtract $4.2 from the original price, $42, and you get $37.8
1. Percent error is

The guess is 15.5mi, and the actual distance is 14.5 mi.
Percent error is

2. The cost will be $31.95*(1+0.075) = $34.35
The 1 represents 100% of the original amount of $31.95, and now we add 7.5% (0.075) to the 100%. In other words we multiply $31.95 by 107.5%.
3. His commission will be $165 out of $4125, or $165/$4215 = 0.039 = 3.9%
4. The principal (amount of money you start with) is $12000, and the interest rate is 15% of that.
15% of $1800 = 0.15*$12000 = $1800
I'm pretty sure the original price would be $90.75 because 3/4 is .75, so all you have to do is add that to the $90