Answers

2014-09-18T15:48:04+05:30
Let the tens digit be T, and the units digit U 

As sum of digits = 15, then T + U = 15 

The value of this number is: 10(T) + U. or 10T + U, and when reversed, we have: 10(U) + T, or 10U + T 

Since the # formed by reversing the digits is 27 less than the original number, then we can say that: 

10U + T = 10T + U – 27 --------> – 9T + 9U = -27 

We now have the following simultaneous equations: 
T + U = 15 _____ (i) 
– 9T + 9U = - 27 _____ (ii)
9T + 9U = 135 _______ (iii) ----- Multiplying eq (i) by 9

18U = 108 _______ Adding eq (ii) and eq (iii) 

U, or the units digit = , or  

Substituting 6 for U in eq (i), we get: T + 6 = 15 ----- T, or the tens digit = 

Now, since the tens digit is 9, and the units digit is 6, this makes the number: 

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2014-09-18T15:54:02+05:30
Let the tens digit be x and the units digit be y
Such that, x + y = 11 ....(1)
The number is 10x + y
The digits are reversed,
the new number = 10y + x

Original number is 27 more than the new number

10x + y = 10y + x + 27
9x - 9y = 27

x - y = 3  ...(2)

On solving the equations (1) and (2)

x = 7 and y = 4
The number is 74.


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