What is the answer to (-3)×(-5)

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

Plz heeeeeeelp plz give me the answer

If the speed of an electromagnetic wave is 100,000 cm/s and its wavelength is 100 cm, what is its frequency? a) 100,000 cycles per second (hz) b) 1 × 10-3 cycles per second (hz) c) 10,000,000 cycles per second (hz) d) 1,000 cycles per second (hz)