Final answer:
To calculate the attack value after a purple fury spell, you take 15% of 1150 points, which equals 172.5 points, and add it to the original attack, resulting in an attack value of 1322.5 points.
Step-by-step explanation:
If a purple fury spell increases the next attack by 15% and the regular attack is 1150 points, we must calculate the increased amount of attack points. The increase can be calculated by taking 15% of 1150, which can be found by multiplying 1150 by 0.15. Therefore, the calculation is 1150 * 0.15 = 172.5 points.
Adding this increase to the original amount gives us the total attack points after the spell is applied. We add the 172.5 points to the original 1150 points to get the new attack value, which is 1150 + 172.5 = 1322.5 points. As a result, the attack value after the use of the spell would be 1322.5 points.