How many multiple of 3 and 5 between 250 and 300, inclusive

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 51
Joined: Wed Jan 13, 2010 3:02 pm
Thanked: 1 times
How many multiple of 3 and 5 between 250 and 300, inclusive

26,27,28,29?

Let mee know weather in GMAT can we get question like these which are lengthy and are quite likely to go wrong, for just one number being missed?

Also please tell me, I am am practising tests from Manhatten TurboCharge Maths. I pick 23 problem solving and 14 datasufficiency questions from book. I get at most three mistakes. Assuming this level of accuracy, Can I get a score of 50 in quant.

Thanks

User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Tue Jan 19, 2010 5:36 am
Due wrote:How many multiple of 3 and 5 between 250 and 300, inclusive

26,27,28,29?
Unfortunately, that question seems to be unclear anyhow if the question was

"How many multiples of 3 or 5 exists between 250 and 300"


there are 17 multiples of 3 , there are 11 multiples of 50 and there are 4 multiples of 15

so total no of distinct numbers is : 17+11 -4 =24 which is not in the list
Always borrow money from a pessimist, he doesn't expect to be paid back.

Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Tue Jan 19, 2010 7:55 am

by mavsee » Tue Jan 19, 2010 8:02 am
The question doesnt say distinct -in which case, the answer would be 28 - which is in the list.
On a seperate note, the way you would solve this to use the following formula.

no of consecutive terms = last term - first term/difference between each term(constant)

eg:No of multiples of 3 -

300-250/3 + 1 =17.
Note that the you count only the closest integer when you divide (300-250) by 3 and avoid the remainder.

You would use a similar approach for muliples of 5 and add both.
[/quote]