I did all the questions related to the quantitative section in the OG13 (PS-DS).
I had on average 20% wrong on the first attempt.
Is it good or weak?
How much have you prepared for Quantitative section as yet? The answer to the question you've asked depends on how far in into your prep you are. As stated in the above comment it also depends on whether you attempted those questions in timed conditions.
If this is early on in your preparation I would advise you to concentrate more on going through the content than questions. Don't worry too much about how many you got right or wrong. If you want to do really well on the quant section- Q50 and above - you will need to have a go at harder problems and maintain your timing through them in the long run.
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