Call the two offers offer A and B respectively.
For offer A, the list price is 5000 pesos with a 15% discount. So you will pay:
[tex]A=5000(0.85)=4250\text{ pesos}[/tex]For offer B, the list price is 5200 with a 20% discount. So you will pay:
[tex]B=5200(0.8)=4160\text{ pesos}[/tex]So the first deal is costing 4250 pesos and second one costs 4160 pesos.
Hence the second deal is better by 4250-4160= 90 pesos.
The second deal is the better deal by 90 pesos.