Answer :
Let the number be x.
According to your question,
x + 3x = 100 ( Equation)
thus, 4x = 100
Thus, x = 100/4 = 25
Thus, the number is 25 (Solution)
According to your question,
x + 3x = 100 ( Equation)
thus, 4x = 100
Thus, x = 100/4 = 25
Thus, the number is 25 (Solution)