Select all the expressions below which represent a 20% discount off the price of an item that originally costs d dollars.

A. 0.8d

B. d-0.2

C. d-0.2d

D. 1-0.2d

The electric field in a certain region of Earth's atmosphere is directed vertically down. At an altitude of 439 m the field has magnitude 50.7 N/C; at an altitude of 361 m, the magnitude is 84.3 N/C.

What is the value of relative humidity when the air is saturated?

A wave has a period of 0.25s. Calculate its frequency.

A boy on the beach holds a spherical balloon filled with air. at 10:00am, the temperature on the beach is 20°c and the balloon has a diameter of 30 cm. two hours later, the balloon diameter is 30.5 cm.

X=3t^2-12t+5 calculate time t=1 and time when velocity zero

What are the average velocity and average acceleration of the tip of a 2.4 cm long hour hand of a clock?

What is the number one and most important rule to remember in soccer?

Why are convection currents; why are they hotter and colder parts of earth

A swimmer is swimming to the left with a speed of 1.0 m/s when she starts to speed up with constant acceleration. The swimmer reaches a final speed of 2.5 m/s over a distance of 5.0 m. How long did the swimmer take to speed up to 2.

An archer defending a castle is on a 15.5 m high wall. He shoots an arrow straight down at 22.8 m/s. How much time does it take to reach the ground?