primary 6 chevron_right Maths chevron_right Ratio chevron_right Singapore

Hi can you help me with this pls it is due tomorrow here is the question for the 1st one ontop:

The ratio of the number of eraser wafi had to the number of erasers Farah had was 5:1 . After Farah gave 25 erasers to wait, the ratio of the number of eraser wafi had to the number of erasers Farah had became 5:3 . How many erasers did Farah had in the end

My teacher need Before Change/Event After (BEA/BCA)

Thank you