Question

Confused in this problem :P
When the digits of a two digit number are reversed, the new number is 36 more than the original number. The units digit is twice the tens digit. What is the original number?

Answer 1

Let digits of original number be x and y.

10x + y + 36 = 10y + x

It also says y = 2x. Substitute and solve.

Answer 2

O so thats how you set it up...

Answer 3

Yes.

Answer 4

Is this correct
y=4?

Answer 5

10x + 2x + 36 = 20x + x
=> 12x + 36 = 21x
=> 9x = 36
=> x = 4
=> y = 8

Answer 6

Can I ask you one question?

Answer 7

Sure.

Answer 8

For the part "36 more than the original number" what if it said 36 LESS THAN
would it be set up like this
10x+2x-36?

Answer 9

10x + y - 36 = 10y + x

Answer 10

You just need to think about how to formulate. You know x is the tens digit and y is the ones digit in the original number. So, the original number will be 10x + y. The "Flipped" number will be 10y + x.

Now, you need to include the "relation" between original number and flipped number.

Flipped number is 36 more than original?
=> 10y + x = 10x + y + 36

Flipped number is half the original number?
=> 10y + x = (10x + y)/2

Flipped number is 10 less than the original number?
=> 10y + x = 10x + y - 10

Etc....!

Answer 11

How do you set up if the sum of the digits is 8?

Answer 12

Like this
10x+y=8?

Answer 13

If sum of the digits is 8, then you simply have x+y = 8 because that is just the simple addition of the digits. Not the "value" of the digits.

Answer 14

Ok then.

Answer 15

Remember, the "number" assigned to a digit is NOT the same as the "value" of that digit.

Answer 16

Ok

Answer 17

In the number 386, the tens digit is 8. But, its "value" is 80.

Answer 18

Hundreds digit is 3 and its value is 300.

Answer 19

Ok