Could you solve this hard probability question?

An interesting probability puzzle about a sock draw-er drawing socks from a sock drawer! Accessible to A-Level and advanced GCSE students!

50 Challenging Problems in Probability: https://amzn.to/3gcwFDP

______________________________________
Free online maths challenge courses:
Primary (age 9-11): https://bit.ly/primarymathschallenge
Junior (age 10-13): https://bit.ly/ukmtjuniormathschallenge
Intermediate (age 13-16): https://bit.ly/intermediatemathschall...
Senior (age 15-18): https://bit.ly/seniormathschallenge
All online courses: https://courses.mathsaurus.com/
______________________________________
Make your own online courses with Thinkific and turn your expertise into a thriving business: https://try.thinkific.com/cyfkxypcaasn
______________________________________
Mathsaurus website: https://mathsaurus.com/
All online courses: https://courses.mathsaurus.com/
Get ready for A-level maths: https://bit.ly/getreadyforalevelmaths
Instagram:   / mathsaurus  
Twitter:   / mathsaurus  
Facebook:   / mathsaurus  
Discord server:   / discord  
Mailing list: http://newsletter.mathsaurus.com/
Tuition/contact: https://mathsaurus.com/contact/tuition/
Calcualtor guide: https://bit.ly/whichcalculator
Setup for online teaching/how I make my videos: https://bit.ly/teachingmathsonline