let

x = the first number

y = the second number

The sum of two numbers is 56:

x + y = 56

The first number is 2/5 of the second number:

x = (2/5)y

by solving the system of equations:

x + y = 56

x = (2/5)y

we find:

x = 16

y = 40

click here to see the step by step solution of the system of equations:

the numbers are 16 and 40.