Question

Sun of digts of two digited number is 7. If 9 subtracted from it, the digits, are reversed. Find the number?



chapter : linear equations in one variable

class : 8th ​

Answer 1

Answer:

Let the one digit be x and other be y.

x + y = 7

x = 7 - y

(10x + y) - 9 = 10y + x

10(7-y) + y - 9 = 10y + 7-y

70 - 10y + y - 9 = 9y + 7

61 - 9y = 9y + 7

61 - 7 = 9y + 9y

54 = 18y

54/18 = y

3 = y

x + 3 = 7

x = 7 - 3

x = 4

therefore, the first number is 4 and second number is 3