Slide39.JPG

Slide40.JPG
Slide41.JPG Slide42.JPG Slide43.JPG Slide44.JPG

This video is only available for Teachoo black users

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Example 10 The sum of a two-digit number and the number obtained by reversing the digits is 66. If the digits of the number differ by 2, find the number. How many such numbers are there? Number is of the form Let Digit at Units place = y & Digit at Tens place = x Given that (Number) + (Reversed Number) = 66 (10x + y) + (10y + x) = 66 10x + x + 10y + y = 66 11x + 11y = 66 x + y = 66/11 x + y = 6 Also, given that Digits of the number differ by 2, So x – y = 2 or y – x = 2 Solving equation (1) & (2) x + y = 6 …(1) x – y = 2 …(2) By elimination method 2y = 4 y = 4/2 y = 2 Putting y = 2 in (2) x – y = 2 x – 2 = 2 x = 4 Hence, x = 4, y = 2 is the solution of equations (1) & (2) Thus, Number is = 10x + y = 10 (4) + 2 = 40 + 2 = 42 Solving equation (1) & (3) x + y = 6 …(1) y – x = 2 …(3) Solving (1) & (3) by elimination 2x = 4 x = 4/2 x = 2 Putting x = 2 in equation (3) y – x = 2 y – 2 = 2 y = 2 + 2 y = 4 Hence x = 2, y = 4 is the solution of equations (1) & (2) Thus, Number is = 10x + y = 10 (2) + 4 = 20 + 4 = 24 So, the numbers which satisfy the given equations are 24 & 42

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.