First, simplify the expression inside the parentheses:

5√1024 = 5√(32 32) = 5 32 = 160

Now the expression becomes:

20/160 * (3/5)^2

Next, simplify the fractions:

20/160 = 1/8

Now we have:

1/8 * (3/5)^2

Now square the second fraction:

(3/5)^2 = (3/5) * (3/5) = 9/25

Now multiply the fractions:

1/8 * 9/25 = 9/200

Therefore, the final answer is 9/200.