A Certain Number Of Two Digits Is Three Times The Sum Of Its Digits.

1.	A Certain Number Of Two Digits Is Three Times The Sum Of Its Digits. If 45 Be Added To It, The Digits Are Reversed. The Number Is?
Answer» LET x and y are the digits of the number with x in ten’s place and y in one’s place. So, 10x+y is the value of the number. Given 10x + y = 3 (x + y) ⇒7x – 2y = 0 …………….(i) And also given that, 10x + y + 45 = 10y + x (∵ digits are reversed⇒ x in one’s and y in ten’s place). ⇒ 9x – 9y = -45 ⇒ x – y = -5 ………………(ii) PUT value of y from eq. (i) to eq. (ii) ⇒ x – (7x/2) = -5 ⇒ x = 2 And y = 7 So the number is 27 Let x and y are the digits of the number with x in ten’s place and y in one’s place. So, 10x+y is the value of the number. Given 10x + y = 3 (x + y) ⇒7x – 2y = 0 …………….(i) And also given that, 10x + y + 45 = 10y + x (∵ digits are reversed⇒ x in one’s and y in ten’s place). ⇒ 9x – 9y = -45 ⇒ x – y = -5 ………………(ii) Put value of y from eq. (i) to eq. (ii) ⇒ x – (7x/2) = -5 ⇒ x = 2 And y = 7 So the number is 27

A Certain Number Of Two Digits Is Three Times The Sum Of Its Digits. If 45 Be Added To It, The Digits Are Reversed. The Number Is?

Answer»

LET x and y are the digits of the number with x in ten’s place and y in one’s place.

So, 10x+y is the value of the number.

Given 10x + y = 3 (x + y)

⇒7x – 2y = 0 …………….(i)

And also given that,

10x + y + 45 = 10y + x (∵ digits are reversed⇒ x in one’s and y in ten’s place).

⇒ 9x – 9y = -45

⇒ x – y = -5 ………………(ii)

PUT value of y from eq. (i) to eq. (ii)

⇒ x – (7x/2) = -5

⇒ x = 2

And y = 7

So the number is 27

Let x and y are the digits of the number with x in ten’s place and y in one’s place.