fractions

This topic has expert replies
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Sat Aug 15, 2009 7:34 am

fractions

by g-manatl » Sat Aug 15, 2009 2:57 pm
Hello Everyone,

What is the most efficient way of solving this problem.

Thanks in advance.

1/40 + 1/41+ 1/42 + 1/43 + 1/44 + 1/45

Master | Next Rank: 500 Posts
Posts: 487
Joined: Fri Mar 27, 2009 5:49 am
Thanked: 36 times

Re: fractions

by dtweah » Sat Aug 15, 2009 7:03 pm
g-manatl wrote:Hello Everyone,

What is the most efficient way of solving this problem.

Thanks in advance.

1/40 + 1/41+ 1/42 + 1/43 + 1/44 + 1/45
Depending on the answer choices there are different tricks around it.

The above sum is less than 1/8

B/c 1/40 + 1/40 + 1/40 +1/40 +1/40 +1/40 = 1/8

So among answer choices I will eliminate all choices greater than 1/8

You definitely NEVER want to do the usual LCM thing on such a question.