Mari has 3 friends who are available to go with her to the movies, but she only has 2 extra tickets. How many different choices does Mari have for which 2 friends to invite?

3 different choices

Step-by-step explanation:

This problem is a combination problem: She has 3 friends, and we want to know how many groups of 2 friends there are. We can solve this using the combination of 3 choose 2:

C(3,2) = 3!(1! * 2!) = 3*2/2 = 3 possibilities

If we call her three friends A, B and C, the groups that can be formed are:

A and B

A and C

B and C

sine

step-by-step explanation:

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have