500 let me know if it’s right i’m not the best at math
A dilation by a scale factor of 6 will cause the radius to increase by a factor of 6. So

. If we plug this value of r into the formula for the circumference of a circle we get

So basically N = 12r. You haven't given me any original radius, so I can't give you a constant for N, but if you do have that original radius you can just plug that into 12r.
Based on your comment, N = 12 * 9 = 108 inches
Maria : 26.50 - 0.25(26.50) = 26.50 - 6.625 = 19.88
19.87 + 0.10(19.87) = 19.87 + 1.99 = 21.86
Edwin : 0.75(26.50) = 19.88
1.10(19.88) = 21.86
and if they each have $ 23, then yes, they both ave enough money to buy the book. They both were correct in their calculations. Because taking 25% off, is the same as paying 75%.....and taking the discount price and subtracting 10% from that, is the same as multiplying by 110%. So they basically worked the same problem, just in a little different way...and they both ended up with the same answer