Math Help Please :D I have a a test tomorrow in this!?

Question

The tens digit of a 2 digit number exceeds its units digit by 4. Twice the number obtained by the reversing digits of the original number exceeds the number by 1. What is the original number?

Answer 1

Any 2-digit number can be written as 10*x +y, where x is the digit in the tens place and y is the digit in the ones place. Reversing the digits, you have 10y+x

Here, the tens digit is 4 bigger than the ones unit: x=y+4

2*(10y+x)=10x+y+1

20y+2x=10x+y+1

19y+2x=10x+1

19y-8x=1

We know x=y+4, so substitute that in:

19y-8(y+4)=1

19y-8y-32=1

11y-32=1

11y=33

y=3

x=y+4=3+4=7

The original number is 73

_/

Answer 2

Step One:   List two digit numbers where the tens digit is greater by four than the units digit...... = 95, 84, 73, 62, 51, 40

Step Two:  reverse the numbers:   73....37

Step Three:  multiply by 2:  37 x 2 = 74

Step Four:  Find Difference:  74 - 73 = 1  IT WORKS!

Answer = 73

Answer 3

The tens digit of a 2 digit number exceeds its units digit by 4.

40

51

62

73 the answer

84

95

15 x 2 = 30

26 x 2 = 52

37 x 2 = 74 I think we have a winner!!

48 x 2 = 96

59 x 2 = 118