function h(n)

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function h(n)

by LevelOne » Sat Jul 04, 2009 8:20 am
Please help with these 2 questions as per the attachments.

Q3:
To furnish a room in a model home, an interior decorator is to select 2 chairs and 2 tables from a collection of chairs and tables in a warehouse that are all different from each other. If there are 5 chairs in the warehouse and if 150 different combinations are possible, how many tables are in the warehouse?

A. 6
B. 8
C. 10
D. 15
E. 30

thanks
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by Robinmrtha » Sat Jul 04, 2009 9:24 am
use the process of substitution...
first
the question can be stated in the following equation (n is the no. of tables)

5!/(3!2!) x n!/{(n-2)! 2!} = 150

or 5 n!/ (n-2)! = 150

use process of substitution
A is the answer

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by LevelOne » Sat Jul 04, 2009 10:21 am
OA is A. Any ideas about the other two questions??

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by ssmiles08 » Sat Jul 04, 2009 12:14 pm
3)

7x + 77y = 350
x+y = n

we need to find a possible value for n.

7(x+11y) = 350

x+11y = 50

x = 50 - 11y

50 - 11y +y = n

50 - 10y = n

10(5 - y) = n

we know all values are integers. 'n' is also an integer. therefore it must be a value divisible by 10. the only value which is divisible by 10 in the answer choices is 40.

IMO C.

2) has been overly discussed in the forums. Please do a search.

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by LevelOne » Sat Jul 04, 2009 12:34 pm
thanks for clarifying, OA is C.