Relativity 000

"A spaceship is travelling at 0.80c, away from Earth. It launches a probe away from
Earth, at 0.50c relative to the spaceship. An observer on the probe measures the
length of the probe to be 8.0m.
Deduce the length of the probe as measured by an observer in the spaceship."
-IB Physics, Paper 3, Section- Relativity, Year- 2020 Oct

Thanks for watching.