Can you please help me with this "trick" problem?

Question

N x 2 + 4 x 5 + 12 x 10 - 320 / 100 = N (Starting Number)

Note: 320 / 100 is not a fraction.

This problem is from left to right.

And N can be any number.

My question is: Why can N be any number?

What is the "trick" here?

PLEASE HELP!

Answer 1

I think I can explain.

In math, we make it a habit to do indicated operations (+,-,X,/) in a

certain order. Your problem is a step by step description of the puzzle.The usual order of doing things doesn"t apply here

Let's analyze this.

Pick a number...........N

Multiply by 2.............2N

Add 4.......................2N........+4

Multiply by 5............10N.......+20

Add 12.....................10N......+32

Multiply by 10..........100N.....+320

Subtract 320............100N

Divide by 100..............N

See what happened? N can be any number because all that jigging

and poking with a

"add this"", "multiply by this" ended up eliminating the constant term

(in your puzzle that was 320), leaving only the variable tern (the 100N

term in your puzzle).

The last step is to simply divide the variable term by its coefficient to

yield N.

And that's all there is to it.

Cheers!

Answer 2

you would never find it from your typing version....((((( n x 2 + 4 ) x 5) +12) x 10) - 320) / 100 = n......multiplication of n on the left is 2 x 5 x 10 = 100, addition/subtraction on the left is (4 x 5 +12) x 10 - 320  = 0

Answer 3

It's because the last two functions cancel all the rest out.

I'll try to explain this, might be a bit shoddy.

Multiplying by 2, then five, then ten is like multiplying by 100. The dividing 100 cancels that out.

HOWEVER, you also added to the problem. So the 4 you added is also multiplied by five and ten (making 200), and the additional 12 is multiplied by 10 (which makes 120). Add those together and you get 320, which you later take away.

I know this explanation is a bit... complex, but think about it. Hopefully it helps, but maybe not. =/

Answer 4

all you have to do is use order of operations and simplify the left side of the equal sign.

N x 2 + 4 x 5 + 12 x 10 - 320 / 100

= {10[5(2N+4)+12] - 320} / 100

= {10[10N +20 +12] -320} / 100

={10[10N +32] - 320} / 100

={100N + 320 - 320} / 100

= 100N / 100

= N