What letter in the alphabet is a line segment

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)

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.

Sara made $253 for 11 hours of work. at the same rate how much would he make for 7 hours of work?