# Can you guess the number?

179 views
asked Feb 2, 2015 in Math

Hi,

Feeling bored???

Are you ready to play an interesting trick??

Let's start.

Think of a number. Follow the below steps.

1. Add 2 with the number

2. Multiply result with 5.

4. Multiply 2 to the resultant number and add it with four.

5. Divide the answer with 10.

Now if you say the resultant value.....I can guess the number thought by you!!!!!

answered Feb 2, 2015 by (21,810 points)

My answer is 16. Can you guess my number?

commented Feb 4, 2015 by Techarena
the number you thought is 13.Am i right????
+1 vote
answered Feb 2, 2015 by victoria
I got the answer 90. 4+2=8 multiply by 5=40+3=43 multiply by 2=86+4=90
commented Feb 2, 2015 by (64,030 points)
4+2 = 8 ?

I think you mean

4+2 = 6

multiply by 5 = 30 + 3 = 33, multiply by 2 = 66. add 4 = 70. Divide by 10 = 7
commented Feb 4, 2015 by Techarena
The number you thought is 87.
+1 vote
answered Feb 2, 2015 by (64,030 points)

I think the secret is you just subtract 3 from the answer to get the initial number...

Here is my reasoning

Let x = number

step 1:

x + 2

step 2:

5(x+2)

step 3:

5(x+2) + 3

step 4

2 * (5(x+2) + 3) + 4

step 5

(2 * (5(x+2) + 3) + 4 )/ 10

So

if R is final total

(2 * (5(x+2) + 3) + 4 )/ 10  = R

2 (5x + 10 + 3) + 4) = 10 R

10 x + 20 + 6 + 4 = 10 R

10x + 30 = 10 R

10x = 10R - 30

divide both sides by 10

x = R - 3