You miss out a few things
1) Electricity and water expense?
2) Materials supply?
3) Your booth/stall setup?
Your monthly expenses is RM2.2k (labour + rental). You plus item no. 1 and no.2 you have your monthly expenses.
Can you estimate how much you can sell and how much you want to charge per cup and per waffer?

Tror,

Your target market is students, and you are selling your goods at above average price. Tell me, are you opening up in Sunway or Monash area?

The IDEAL price to achieve your above estimated volume would be RM2.50 for bubble tea and RM2 for wafer. Anything more than that, students will not buy, unless you open up in the 2 areas mentioned.

"i estimate will get around 35cups of bubble tea per day and 30 waffer.. which give me profit of Rm165 per day and Rm4950 per month"

Tell me, which college has classes 7 days a week, 30 days per month? Unless you are opening up in the student accommodation, then you might be able to achieve sales every day. Also, for 35 cups of bubble tea and 30 pieces of wafers, your daily profit would only be RM90 (on the assumption that your price at RM2.50 and RM2). Your monthly profit based on 20 days would be RM1,800. Deduct your rental and the salary, you will be at a loss. That is not including utilities.

Tror, you're lack of business experience. You're from the engineering background trying to get your hands on one so you really need to put in a lot of efforts especially in doing research. Not to mention about your product/services that you intend to offer, you're putting yourself in high risk when you have no knowledge at all and yet you plan to have someone(staff) looking over the business. It's not as simple as you think, set up the stall, having someone there to manage on your behalf while you assume based on your calculations you'll be getting that amount of profits every month. Many things that you need to take into considerations.