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 start with?

Answer 1

Let Dennis thought of a number = P
step 1:- He adds 0.5 to number , then number = P + 0.5
Step 2:- 4 is multiplied with (P + 0.5) , e.g., 4(P + 0.5) = 4P + 2
Step 3 :- 2 is Subtracted from (4P + 2) ,e.g., 4P + 2 - 2 = 4P
Step 4 :- 2 divides 4P by 2 e.g., 4P/2 = 2P
Step 5 :- his final answer is 2P = 48
⇒ 2P = 48
⇒ P = 24

Hence, Dennis thought a number = 24

Answer 2

Solution:-

let dennis thought of a number is = x,

then ,
acourding to quetion:-

$\frac{(x + 0.5) \times 4- 2}{2} = 48 \\ 4x + 2 - 2 = 96 \\ 4x = 96 \\ 4x = 96 \\ x = \frac{96}{4} \\( x = 24)ans$
dennis thought of a number is 24 ans

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