Hydrogen bonds exists between the DNA strand and its complementary strand such that; there are two hydrogen bonds between every A and T, and three between every C and G.
Therefore; in this case there will be (2 ×3 ) +(3×3) = 15 hydrogen bonds for the above strand. this is because Adenine binds to Thyamine with two bonds (3 pairs) and Guanine binds to Cytosine with three bonds (3 pairs).