Check the picture below. You can pretty much count the units off the grid.
recall that A = (1/2)bh.



A medical researcher need to select 6 people out of 13 people who have volunteered for the test in
To find, how many ways can 6 people be selected.
=
=


Step-by-step explanation:
1:d
2:c
3:a
4c
5:b
i think so