There are 10 doors to a coliseum. In how many ways can a person go in and out if one can enter any door but leave using another door? Use permutation formula (P(n, r)) to solve.

90 is the answer

Step-by-step explanation:

P(10,2) = = =

10x9

=90

answer: ouch. thats difficult

step-by-step explanation:

the correct option is 2.

step-by-step explanation:

according to the given information triangle abc is a right angle triangle with right angle at a. segment ab is 5 and segment ac is 7. point d is on segment bc and angles adb and adc are right angles.

it is given that triangles abd, cad, and cba are similar.

two triangles are similar if their corresponding sides are proportional.

in triangle cba, using pythagoras theorem

                      )

triangle abd and cba are similar,

                            (2)

triangle cad and cba are similar,

                      )

using (1), (2) and (3), we get

hence proved.

therefore option 2 is correct.