jmc

Call the amount of money Larry has $a$ and the amount of money Lenny has $b$. We can use the following system of equations to represent the given information: $$\begin{array}{rl}a+b& =35\\ a& =\frac{2}{5}\cdot b\end{array}$$ Substituting for $a$ into the first equation gives $\frac{2}{5}b+b=35$. Solving for $b$ gives $\frac{7}{5}b=35$, or $b=25$. Thus, $a=35-25=10$. So Lenny has $25-10=\boxed{15}$ more dollars than Larry.