What is 35% of 4/13 of 845?
Options
A) 58
B) 69
C) 80
D) 91
E) 102
This problem can be solved easily if we just use approximation: 35% is a little over 1/3, while 4/13 is a little less than 4/12, which is 1/3. Thus, the answer is about 1/3 of 1/3 of 845, or 1/9 of 845. Since the first 1/3 is a slight underestimate and the second 1/3 is a slight overestimate, the errors will partially cancel each other out. Our estimate will be relatively accurate.   The number 845 is a bit more than 810, so (1/9)*845 will be a bit more than 90.   Keeping track not only of your current estimate, but also of the degree to which you have overestimated or underestimated , can help you pinpoint the correct answer more confidently.   The closest answer is 91, so this is the answer to choose.   The answer is 80.
<result>C</result>
What is 35% of 4/13 of 845?