Let the other number be = y

Since,

\({Arithmetic Mean} = \frac{{Sum of numbers}}{{Total number of variables}}\)

or \(20 = \frac{{x + y}}{2}\)(since the number of variables is x and y i.e 2)

or \(x + y = 40\)

or \(y = 40 - x\)

So the other number in terms of x is = \(40 - x\)
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