First, you should figure out which sum of money is larger.
0.15 * 1500 = 225
0.25 * 950 = 237.5
After figuring this out, one would realize that 25% of $950 is larger than 15% of 1,500.
Therefore, if someone offers to give you 15% of $1,500 or 25% of $950, you should choose 25% of 950.