Study the following bar graph that shows the number of students enrolled for different courses in institutes A and B during 5 years, and answer the question that follows.
A = The total number of students enrolled in A during 2015 and 2018.
B = The total number of students enrolled in B during 2014 and 2015
What is the value of B : A?
1
17 ∶ 13
2
13 ∶ 17
3
13 ∶ 12
4
12 ∶ 13