This question is from linear equations in two variables in which we have been asked to find the number if the sum of a two digit number and the number obtained by reversing the order of the digits is 121 and if the digits differ by 3.
Kindly give me a detailed solution of this question
RS Aggarwal, Class 10, chapter 3E, question no 18
Let the two digit number be 10x+y
On reversing its digits, we get the number 10y+x
Given, (10x+y)+(10y+x)=121
11x+11y=121
=> x+y=11 — (1)
Given, x−y=3 — (2)
Adding (1) and (2), we get
2x=14 => x=7
Substituting x=7 in the equation (2), we get 7−y=3⇒y=4
Hence, the number is 74 or 47