For this problem, we can use the formula for combinations, which is:
, where we have <em>n</em> objects choosing <em>r</em> at a time
7*6 is 42, and 42/2 is
21. There are
21 possible combinations
:)
I think -5, sorry if I’m wrong.
75% of 56 is .75 * 56
.75 * 56 = 42
Because you are decreasing, you subtract 42 from 56.
56 - 42 = 14
A 75% decrease of 56 books would leave 14 books.
That dot means multiplication