Question

there are 10 students in a social studies class. three students will be selected to present their term projects today. In how many different orders canthree students be selected?

Answer 1

combinations of 10 three at a time
=
10!/ [ 3! (10-3)! ]

= 10 * 9 * 8 *7* .......1 /[3*2(7*....1) ]

= 10 * 3 * 4

= 120

or look up binary coefficient (10,3)
= 120

or look at Pascal's triangle row 10, element 3 (the eleventh row, fourth element really since zero counts) again 120

Answer 2

thank you so much