To minus,
-20% for commission
-20% for fuel
-10% for wear and tear
= 50% nett pay (roughly rm 4000 per month)
= roughly 4000/30 = RM 133 per day

32 jobs per day, if 15 minute per job means
= 480 minutes of driving (if wait time about 10%) that means
= 480 x 1.10
= 528 minutes = 8.8 hrs job per day (roughly)

=> meaning RM 133 / 8.8 = Rm 15.11 per hour job

If you can find a part time job that pays RM 15.11/hr don't do grab, actually tuition job can also give you so much.

Driving + waiting for rides for 8.8 hours per day can damage your health badly unless you are thinking of TEMPORARY or PART TIME or if you have NO other better choice.

BTW - uncle drove GRAB for a few months exploring the idea if to have a fleet of GRAB cars and decided not to venture further.