Solution:Let's assume the given number as 'x'.
According to the given question, one half of the number divided by 6 and the other half divided by 4 are added. So, the expression for the given question is:
(x/2)/6 + (x/2)/4
Simplifying the above expression, we get:
x/12 + x/8 = (2x+3x)/24 = 5x/24
The above expression is the correct answer if the student had followed the instructions correctly.
But the student divided the given number by 5. So, the expression the student got is:
x/5
According to the given question, the student's answer is 4 less than the correct answer. So, we can write:
x/5 = 5x/24 - 4
Simplifying the above equation, we get:
24x = 25x - 480
x = 480
Therefore, the given number is 480.
Thus, the correct option is (c) 480.