Aset of twins, andrea and courtney, are initially 10 years old. while courtney remains on earth, andrea rides on a spaceship which travels away from earth at a speed of 0.50 c for five years (as measured by courtney), then immediately turns around and comes back at 0.50c . when andrea returns, courtney is 20 years old. how old is andrea upon her return?

she is 20 at least I think not entirely sure about that!

Step-by-step explanation:

if Courtney is here on earth while her twin Andrea is in space she ages by the same rate just it's a little bit different. no one knows how long Andrea has slept for or how long she was up there for.

.632

step-by-step explanation:

6 * 1/10 = 3/5

3*0.01 = 0.03

3/5 + 0.03 = .63

2*0.002 = .002

.63 + 0.002 = .632