40%
Because, 2/5 equals 4/10. 10x10=100, so 4x10=40, so 40%.
C because the most common factor would be 15 cus 15 goes into 15 once, 30 twice, and 60 four times which is an easy way of figuring out the the greatest common factor and I hope that helped :-)
54,000 if the column before is 5 or more, you round up
