Product of the two digits of a positive no. is 18, when 63 is subtracted from the no. the digits interchange their places. Find the no.

Asked by Murali | 5th Oct, 2013, 10:03: PM

Expert Answer:

To solve any word problem, we would suggest you to analyse the given information and move step by step, as shown below.
 
 
 
Let the ten’s place digit of a two digit number be x and the unit’s place digit be y.
So, number = 10x + y
 
(A two digit number say 52 can be written as 5 x 10 + 2)
 
Now, given, product of digits is 18.
Hence, xy = 18 or y = 18/x               ... (1)
 
Now ,when the digits are interchanged, then the number becomes 10y + x
(In this case, ten's digit will be y and ones place will be x)
 
Again, it is given that when 63 is subtracted from the no. the digits interchange their places. Thus, we get,
10x + y - 63 = 10y + x
Now, from (1) put the value of y.
10x + 18/x - 63 = 180/x + x
Now, you can solve the above equation to get x = 9
 
Hence, 
Tens place digit = 9
Units place digit = 18/9 = 2
Number = 10x + y = 10 x 9 + 2 = 92

Answered by  | 5th Oct, 2013, 11:51: PM

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