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 no. be x
$((x + 0.5)4) - 2 \div 2 = 48 \\ 4x + 2 - 2 = 48 \times 2 \\ 4x = 96 \\ hence \: x = 24$
hope it helps....

Answer 2

Let the number be x

Adds 0.5 to that number

⇒ x + 0.5

Multiplies the new result by 4

⇒ 4( x + 0.5)

Subtracts 2

⇒ 4( x + 0.5) - 2

Divides the number by 2

⇒ [ 4( x + 0.5) - 2 ] ÷ 2

Final answer is 48

⇒ [ 4( x + 0.5) - 2 ] ÷ 2  = 48

Solve x:

[ 4( x + 0.5) - 2 ] ÷ 2  = 48

4( x + 0.5) - 2   = 96

4( x + 0.5)  = 98

x + 0.5  = 24.5

x = 24

Answer: The number is 24