Suppose Xiao Li is X years old and Lao Li is 56-x years old. When Lao Li was this age, Xiao Li was (56-x)-x=(56-2x) years old.

So there is: 56-x+(56-2x): (56-x) = 5: 4.

x =24，

Then Lao Li's age is 56-24=32.