help in econ?

Question

I need help on this, this class was easy but the numbers and functions get to me, thanks

demand function P=2,000-50Q
a) to sell 20 units of Q, what price would have to be charged?

b) if firm sets a price of $500, how many units of Q would be sold

c) what is the price elasticity of demand if price equals $500

d) at what price if any, will the demand of Q be unitary elastic

Answer 1

a) 1,000
b) 30
c) 1/30 / 50/500 = 1/3
d) 21 Units (or is it 20?? I am doing too much math and need to stop now. lol)
from 20 to 21 change in q is 1/20
change in p is 50/1000
divide change in q by change in p = 1