I noticed when I was doing this problem that the only way to solve this problem in a reasonable amount of time was to take an approximation at an early phase of the calculation, specifically you must let 60/66.6 ~ 1

now once you do that you can quickly solve the problem.

My question is this--- how do I know when to do these time saving tricks--- im guessing you learn mostly by practicing but if someone could point me to some more helpful info on this subject i would be interested

thx