Answer:
 
 +
 + 
 = n +1.
 = n +1.
Number = 12.
Explanation:
Given : The sum of one-third of a number and three-fourths of the number exceeds that number by one.
To find : Which equation could be used to find the number.
Solution : We have given a statement 
Let a number = n
According to question 
One third of a number = 
 .
.
Three - fourths of the number = 
 .
.
Sum of their is exceeds that number by one.
 +
 + 
 = n +1.
 = n +1.
Taking common denominator
 = n+1 .
 = n+1 .
 = n+1.
 = n+1.
On subtracting n both sides.
 -n = 1
 -n = 1
Taking common denominator 
 = 1
 = 1
 = 1
 = 1
On multiplying by 12 both sides
n= 12.
Therefore, 
 +
 + 
 = n +1.
 = n +1.
Number = 12.