Multiply minutes a night X 5 times a week.
Student A 20 minutes X 5 = 100 minutes.
Student B 4 minutes X 5 = 20 minutes.

Multiply minutes a week X 4 weeks a month.
Student A reads 400 minutes a month.
Student B reads 80 minutes a month.

Multiply minutes a month X 9 months.
Student A reads 3600 minutes in a school year.
Student B reads 728 minutes in a school year.

Student A reads the equivalent of ten whole school days a year.
Student B reads the equivalent of only two whole school days a year.
By the end of 6th grade Student A and Student B maintain these same reading habits . . . .

Student A will have read the equivalent of 60 whole school days and Student B will have read the equivalent of only 12 school days. One would expect the gap of information retained will have widened considerably so, undoubtedly, will school performance. How do you think Student B will feel about him/herself as a student?

Which student reads better?
Which student would know more?
Which student would write better?
Which student would have a better vocabulary?
Which student would be more successful in school and life?