If the coefficient of \( x^{10} \) in the binomial expansion of \( \left( \dfrac{\sqrt{x}}{5^{1/4}} + \dfrac{\sqrt{5}}{x^{1/3}} \right)^{60} \) is \( {5^{k}}{} .l\), where \( l, k \in \mathbb{N} \) and \( l \) is co-prime, to \( 5 \), then \( k \) is equal to _______.
