Can 2 people surive off $150 a week?

I have implemented an envelope budget into our financial plan. An envelope budget is where you set aside money in designated envelopes for designated purposes.
Here is how our breakdown:

Gas Envelope $70
Food Envelope $50
Entertainment/Miscellaneous $30

Total $150

I am using cash because I feel it is symbolic because "when it's gone it"s gone" and we tend to not think about our account balance that much when we swipe our debit cards all the time.

I even busted out my markers and color coded our envelopes! Fun little mini project while I was making dinner for Prince Charming.
That's another thing - I was reading another pf blog and they used alias names. So consider me Cinderella (Cindy for short) and the hubby Prince Charming.