Susan is choosing a 2-letter password from the letters a, b, c, d, and e. the password cannot have the same letter repeated in it. how many such passwords are possible?

1st letter can be any of 5 letters

 2nd letter can be 5-1 any of 4 letters

 5*4 = 20

there are 20 possible passwords

5

10

15

20

25

30

35

40

45

50

55

answer: the sun

explanation:

water cycle describes the evaporation of water from earth's surface, formation of clouds and precipitation water back onto the surface of earth. seventy percent of the earth is covered with water in the form of seas and oceans. the heat of the sun causes the evaporation of water from the surface of the ocean. the water vapors rise and condense to form water droplets. the collection of these water droplets form clouds which rain down again.

the evaporation of the oceans surface water as part of the water cycle is caused by the sun