Respuesta :

Answer:

20

Step-by-step explanation:

if you add 20 to 20 you get a sum of 40

if you subtract 20 from 40 you get a difference of 40

Answer:

30 & 10

Step-by-step explanation:

Let be two numbers be A and B

A+B=40

A−B=20

Add two equations

We get

A+B+A−B=40+20

2A=60

A=30

as we know A put  this in one of the equation

30+B=40

B=10

A=30 and B=10