Question

Dennis thinks of a number. He adds 0.5 to that number and then multiplies the new result by 4. He then subtracts 2 and divides the number by 2. His final answer is 48. What number did Dennis start with?

Answer 1

Let the number that dennis begins with be x. first we get x+0.5 on the second operation we get (x + 0.5) * 4 then we get x + 0.5)*4  - 2 lastly we get (x + 0.5) *4–2 /2 therefore we get that (x+ 0.5)*4  - 2/2 = 48  

Or, (x + 0.5)*4 – 2= 48*2  

Or, (x+0.5) * 4 = 96 +2  

Or, x + 0.5 = 98/4  

Or, x = 24.5-0.5  

Therefore, x= 24