For each determine the scale factor used to dialate figure a

My teacher taught me to use the formula new/old. Figure A is the old and Figure A' is the new because that’s its new dilation. For problem A if u divide or simplify 10/12 it would be 5/6 and 20/24 is also 5/6, so the scale factor is 5/6.

72 is the mode because it shows up the most number of times

Ithink it’s b because it say 3 plastic rings and all the balls