Question

16. Write all the two-digit numbers in which the sum of the digits is 9.​

Answer 1

Answer:

18,27,36,45,54,63,72,81,90

Answer 2

Step-by-step explanation:

let the unit place digit of a two-digit number be x.

Therefore, the tens place digit = 9-x

∵ 2-digit number = 10 x tens place digit + unit place digit

∴ Original number = 10(9-x)+x

According to the question, New number

= Original number + 27

⇒10x+(9−x)=10(9−x)+x+27

⇒10+9−x=90−10x+x+27

⇒9x+9=117−9x

⇒9x+9x=117−9

⇒18x=108

⇒ x=108/18=6

Hence, the 2-digit number = 10(9-x)+x = 10(9-6)+6 = 10 x 3 + 6 = 30 + 6 = 36