Joh Tan's answer to Thanu's Primary 6 Maths question.

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Joh Tan
Joh Tan's answer
1 answers (Tutor Details)
1st
In case it is not clear, 52/72 of the book is what is read by Chris at first since 20/72 is read by Chris in 20 days.

Also, to explain the last part, I divided both sides by 52/72 hence multiplied by 72/52 (you have to flip when changing a divide to multiply) and then multiply both sides by 1/12 to get what Chris read in 6 days (which is 1/12 of the book).