The door code outside a house often consists of either pressing A or B and then a code with free digits. Suppose you do not know the code, but try your way. How long would it take to test all combinations if each trial takes 10 seconds?
Round to whole hours.

6 hours

Step-by-step explanation:

2 option for letter

10 for each digit

2×10×10×10

2000 trials

2000×10

20,000 seconds

20000/3600

5.5555555556 hours

answer: the proof is mentioned below.

step-by-step explanation:

since, given:   lines bc = ef

prove:   lines ac > ef

          statements                                           reason

1. bc=ef                                           1. given

2. ac= ab+bc                                 2. because b is the point between the  

                                                            line segment ac

3.   ac > bc                                       3. because if a line segment is equal to

                                                          the sum of two line segments then it is

                                                          always greater then each of these

                                                          individual line segments

4. ac > ef                                         4. by equality property.

130 degrees. i have no other way to explain