How many hydrogen bonds are present between complementary nitrogen bases of a DNA with  5 turns and 20 Adenines?

1 turn = 20 nucleotides ; 5 turns = ?

20/1 × 5 = 100 nucleotides

A+T+G+C = 100

 20+20+G+C=100

G+C= 100-40 = 60 (30+30)

Hydrogen bonds between A&T = 20×2 = 40

Hydrogen bonds between G&C = 30×3 = 90

Total hydrogen bonds 40+90 = 130