I used the Old Change New method and cross multipled
I multiplied $48.76 * 115% (100% + 15%) which equal to 5607.4
So I divided that 5607.4 by 100% and it equals to $56.074 or juat round it to $56
Check: $56 > $48.76 by 15% so the answer is $56 after 15% tip