a number consisting of two digits is 7 times the sum of its digits. when 27 is subtracted from the number the digits are reversed. find the number.

Asked by  | 18th Jul, 2012, 10:44: PM

Expert Answer:

Answer : Given : a number consisting of two digits is 7 times the sum of its digits. when 27 is subtracted from the number the digits are reversed. 
 
To find : the number.
 
As the number is a two digit , then let x be tens's place and y be one's place.
Therefore the two digit number would form as 10 x +y 
 
according to the question,
a number consisting of two digits is 7 times the sum of its digits.
=> 10 x + y = 7( x+y) 
=> 3x-6y=0
=> x = 2y ..........................................(1)
 
when 27 is subtracted from the number the digits are reversed.
After reversing the digits, the number = 10 y +x 
=> (10 x+ y )- 27 = 10y + x
=> 9 x- 9y = 27
=>x -y = 3 ........................(2)
 
Substituting the value of x from eq (1) to eq(2) , we get
=> 2y-y = 3
=> y = 3
 
x= 2y
=> x = 2(3) = 6
Therefore the number is =  10 (6) + 3 = 63

Answer : the required two digit number is 63

Answered by  | 19th Jul, 2012, 12:03: AM

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