The coefficient of x5 in the expansion of 1+x25(1+x)4 is
1+x25(1+x)4
= 5C0+5C1x2+5C2x4+…x 4C0+4C1x+4C2x2+4C3x3+4C4x4
∴ Coefficient of x5 in 1+x25(1+x)4
=5C2×4C1+4C3×5C1=60