Question

Dennis thought 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 starts with?

Answer 1

let number be x
add 0.5 =x + 0.5
multiply by 4 = (x+0.5)4
= 4x+2
subtract 2 = 4x+2-2 =4x
divide by 2 = 4x/2
4x/2= 48
4x =2×48
x= 2×48/4
x= 48/2
x=24 is answer

Answer 2

Let the no. be x.
According to the question,
When 0.5 is added = x+0.5
Further question gives us the equation
=> [4(x+0.5) - 2] /2 = 48
=> [(4x+2. 0) - 2] /2=48
=> 4x=48×2
=> 4x= 96
=> x= 96/4
=> x=24
....... Hope this will help you