Let the first number be = x
Then the second number = 2x
The third number = 2x - 5
Their sum = 55
This can be written in an equation as =
x + 2x + 2x - 5 = 55
= x + 2x + 2x = 55 + 5 ( transposing -5 from LHS to RHS changes -5 to +5 )
= x + 2x + 2x = 60
= 5x = 60
= x = 60 ÷ 5 ( transposing ×5 from LHS to RHS changes ×5 to ÷5 )
= x = 12
The first number = x = 12
The second number = 2x = 2 × 20 = 24
The third number = 2x - 5 = 24 - 5 = 19
Therefore , the three numbers are 12 , 24 and 19 .
