# SAT math counting problems

• 07-20-2013, 04:27 PM
Jack
SAT math counting problems
SAT math counting problems

I need help with the following question:

"In how many different ways can 4 students be seated in two seats?"

Thanks!!:D:D
• 07-20-2013, 04:56 PM
Oliver
SAT maths counting problem permutations
SAT maths counting problem permutations

Quote:

"In how many different ways can 4 students be seated in two seats?"
The number of ways you can change the order of a set of objects is called the number of PERMUTATIONS of that set of objects.

The total number of ways of arranging n objects, taking r at a time is gibe by the following formula:

, where

So, in your case, you have 4 students taking 2 at a time

ways.

The above calculations could be done easily in your GDC casio fx-9860GII SD for example as follows:

OPTN>PROB>nPr and set n=4 and r=2

Another way to solve this problem is that the first seat can be filled with 4 ways and the second with the remaining 3ways(students). So, the total ways are 4x3=12

Hope these help!!:D
• 07-20-2013, 04:56 PM
Jack
Thanks Oliver!!