Question

find two number such that one them exceed the other by 18 and their sum is 92

Answer 1

let the smaller number be x
so other number is x+18
sum of both is 92
so
x+x+18=92
2x=92-18
2x=74
x=37
one number is 37
other is 37+18=55

Answer 2

here is your answer mate..
One Number = x
Other Number = y 
x=y+18 ...............(1) 
x+y=92................(2) 
Put the value of x from (1) to (2)
y+18+y=92
2y=92-18
2y=74
2y/2=74/2
y=37
Put the value of y in (1)
x=37+18
x=55 


Check
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Sum of numbers = 55 + 37 = 92 

one Number = 55
Other Number = 37
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Difference = 18