Jimmy found five numbered card, 1, 2, 3, 4, and 5 under his brother bed. in how many ways can he choose ( Jimmy , not arranging the cards) three cards from the five cards? ​

Need ! a certain ultraviolet ray has a frequency of 1 × 1016 hz, and a certain infrared ray has a frequency of 2 × 1012 hz. which of the following is true? a. the frequency of the ultraviolet ray is fifty thousand times the frequency of the infrared ray. b. the frequency of the infrared ray is fifty thousand times the frequency of the ultraviolet ray. c. the frequency of the ultraviolet ray is five thousand times the frequency of the infrared ray. d. the frequency of the infrared ray is five thousand times the frequency of the ultraviolet ray.