Change 8% to decimal ⇒ 0.08
Service Charge: 0.08 (Php 860) = Php 68.80
The service charge is Php 68.80
Php 860.00 + Php 68.80 = Php 928.80
The other way to compute the total bill including service charge:
Php 860 x 1.08 = Php 928.80
The total bill including service charge is Php 928.80