I need help on this

Answer:
25% off
Step-by-step explanation:
Let's say we have an item that costs $20
1: 15% off then 10% off
100-15=85
20*0.85=17
100-10=90
17*0.9=15.3
2: 10% off then 15% off
100-10=90
20*0.9=18
100-15=85
18*0.85=15.3
3: 25% off
100-25=75
20*0.75=15
The best deal is 25% off
Hope this helps!