<p>@AmerigoRound I know this is two days late, but the first time I took this test, I got a 610 because I was unable to answer many questions because of the time restraint. I just retook it and got a 790 with two years in between the two tests and no extra studying. I had enough time for all of the questions (though not really enough time to go back and check my work). Honestly, for me (the first time) it was nervousness and the fact that it was the first standardized test I had taken in 6 years, so I was out of practice. Being relaxed is key - for my whole life I’ve had very bad anxiety when it comes to timed activities, so I would be stressing out so much and trying to move through the questions so quickly that I would either make stupid mistakes or get distracted really easily and spend way too much time on each problem. Having familiarity with the test and being relaxed should help your kid the next time around 
I would also recommend that he look at some practice problems - not necessarily for learning the material, but for getting a feel for what good strategies are for different types of problems (I believe that there isn’t any need to go buy a book - the online questions from College Board and other resources will serve this purpose just fine).</p>
<p>I hope this helps :)</p>