HELP ME! Someone please help and give an explanation if you can!!!

Answer:
a = 4/3
Step-by-step explanation
First we know that 1/3 over 5 means:
1/3 x 1/5 = 1/15
then using butterfly method
we can solve 1/15 = a/20:
we cross multiply so we get a x 15 = 20
isolating the variable we get the answer 20/15 which is equal to 4/3
Hope this helps :)