A hot air balloon plus its cargo has a mass of 400 kg, and it ...

[xroflmao]

A hot air balloon plus its cargo has a mass of 400 kg, and it holds 700 m3 of hot air. It is floating at a constant height in air with a density of 1.29 kg/m3. What is the density of the hot air in the balloon?
 
  A) 1.39 kg/m3
  B) 0.72 kg/m3
  C) 0.57 kg/m3
  D) 0.86 kg/m3
  E) 0.43 kg/m3

Question 2

The reflecting surfaces of two plane mirrors are perpendicular to each other. How many images of himself will a person standing at a certain distance from the intersection of these mirrors see?
 
  A) 1
  B) 2
  C) 3
  D) 4
  E) 5

[succesfull]

Answer to Question 1

B

Answer to Question 2

C

[xroflmao]

TYSM

[yeungji]

Excellent