Pretty easy question.
If Mang Pedro collected P40 for 48 customers, that would mean (40)(48).
(40)(48) is 1920.
If you were going to deduct half of the total, that would mean 1920 ÷ 2.
OR
1920(1/2)
Which is P960.
Therefore, the total pesos Mang Pedro collected on Sunday is 960.