Go to My Error Log Learn more. Hello Guest! Signing up is free , quick, and confidential. Register now! Already registered? Sign in! E-mail address:. Confirm password:. Login or E-mail. Is there something wrong with our timer? Let us know! I'll try it now. Request Expert Reply. Please wait Nov Applying to BSchools in Round 2? Free Class session with Veritas Prep. GMAT vs. EA: Which is right for you? Subscribe to the world's most powerful GMAT channel!
Free full-length test! Are you applying to top business schools in Round 2? Attend this webinar to learn a methodical approach to recall rules with ease and score consistently high on GMAT SC questions. Attend this free geometry webinar to learn to visualize the solution, enhance comprehension and solve level geometry questions in Quant with ease.
With free trial classes, you can work with a 99th percentile expert free of charge. Learn valuable strategies and find your new favorite instructor; click for a list of upcoming dates and teachers. Sample EA problems and more. How many zeros does ! Find Similar Topics. Show Tags. Own Kudos [? Add Notes. Hide Show timer Statistics. Find how many times the factor 5 is contained in !. That is, we have to find the largest such that !
So, the answer is The correct answer is B. I have absolutely no Idea what they are telling me Can someone please post a simple explanation for the rationale behind the explanation, or even better provide an alternative simple approach? Originally posted by AndreG on Sep 07, pm. Last edited by Bunuel on Feb 20, am, edited 1 time in total. Most Helpful Expert Reply. Re: How many zeros does ! Show Spoiler. General Discussion. You never divide by another prime factor for those type of questions?
What does this question test? It asks for the number of zeros ! If a number ends with zero it has to be a multiple of So essentially we have to find out how many times in !
But multiplication by 10 also happens when multiplication by both 5 and 2 happen. The base 5 problem is actually a fair bit easier than the base 10 problem, but for the sake of convention we'll look at the base 10 before the base 5.
First lets make sure we know what is meant by ! The answer is The clever bit here is thinking what numbers when multiplied together will end in a zero, if asked you how many zeros were on the end of 3 x 3 x 3 x 3 x 3 x 1,, you wouldn't need to do the sum to know the answer is 6.
So the product of what numbers when multiplied ends in a zero: When one of the things being multiplied ends in zero itself. A number ending in 5 multiplied by an even number. Below is tabulated the origin of all the zeros: Number Zeros Number Zeros 2 95 1 90 1 85 1 80 1 75 2 70 1 65 1 60 1 55 1 50 2 45 1 40 1 35 1 30 1 25 2 20 1 15 1 10 1 5 1 Total 12 Total 12 So that's it then there are 24 zeros on the end of !
Another way of thinking of this is with respect to the factors of 5. That is to say the number of times you can divide a number by 5 without getting a non integer result. The table above is in fact an account of all the factors of 5 in the range 1 to Obviously some numbers have more that one factor of 5. Now the base 5 problem The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. How many zeroes are in ! Ask Question. Asked 9 years, 6 months ago. Active 3 years, 11 months ago. Viewed 25k times. Martin Sleziak Matt Matt 2, 5 5 gold badges 32 32 silver badges 46 46 bronze badges. Show 8 more comments. Active Oldest Votes. Matt 6 6 bronze badges. I left it in because I like the formula, and because I used it in a comment to lab bhattacharjee's answer.
0コメント