<p>I think those questions are fair game difficulty-wise for the PSAT. There were some pretty tricky ones in past years. </p>
<p>The first one is quite simple: if y=3f(x-1), think how y differs from f(x). the (x-1) means the graph is just shifted right one unit, so range (vertical values) is not affected by that. the 3 makes the graph three times as tall, so if the highest value of f(x) is 6, three times that is 18.</p>
<p>The second is also relatively simple. They give both the proportions in terms of red marbles. If the number of red marbles is 5/6ths of one number and 6/7ths of another number, it must be a common multiple of both 5 and 6. The LCM of 5 and 6 is 30, so that is the number of reds. Then just multiple 30 by 6/5 to get the number of whites and by 7/6 to get the number of blues, 36 and 35 respectively, and add them all up to 101.</p>