One of the two digits of a two-digit number is twice the other digit If you interchange the digits of - Maths - Linear Equations in One Variable

Question

One of the two digits of a two-digit number is twice the other
digit If you interchange the digits of the two-digit number and add
the resulting number to the original number, u get 66 What is the
original number?

Manbar Singh · Accepted Answer

Let the digit at ones place = xThen the digit at tens place = 2xNow, original number = 10×2x + x = 20x + x = 21xWhen the digits are reversed, then new number = 10×x + 2x = 10x + 2x = 12xNow, according to question :    21x + 12x = 66⇒33x = 66⇒x = 6633 = 2So, original number = 21×2 = 42orLet the digit at tens place = xThen the digit at ones place = 2xNow, original number = 10×x + 2x =12xWhen the digits are reversed, then new number = 10×2x + x = 21xNow, according to question :    21x + 12x = 66⇒33x = 66⇒x = 6633 = 2So, original number = 12×2 = 24

One of the two digits of a two-digit number is twice the other digit.If you interchange the digits of the two-digit number and add the resulting number to the original number, u get 66. What is the original number?