The following table shows the marks scored by 2 students in 5 different subjects.

N = Total marks of student 1 in subjects 1 and 4 taken together
M = Total marks of student 2 in subjects 3 and 5 taken together
What is the value of N : M ?

12 : 13

N = Total marks of student 1 in subjects 1 and 4 taken together

= 40 + 32

= 72

M = Total marks of student 2 in subjects 3 and 5 taken together

= 35 + 43

= 78

Ratio of  N  :  M

= 72  :  78

= 12  :  13