Sum
digits of
two digit
number is 7. When we interchange the
digit, it is found that the resus
number is quäler
original number by 27. What is the
number
than the
atroo digit
Answers
Answer:
27
Sum
digits of
two digit
number is 7. When we interchange the
digit, it is found that the resus
number is quäler
original number by 27. What is the
number
than the
atroo digit
Answer:

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Ncert solutions
Grade 8
Mathematics
Science

Chapters in NCERT Solutions - Mathematics , Class 8

Exercises in Linear Equations in One Variable

Question 3

Q3) Sum of the digits of a two-digit number is 9. When we interchange the digits, it is found that the resulting new number is greater than the original number by 27. What is the two-digit number?
Solution
Transcript
Solution:
Let the unit place digit of a two-digit number be x.
Therefore, the tens place digit = 9-x
\because∵ 2-digit number = 10 x tens place digit + unit place digit
\therefore∴ Original number = 10(9-x)+x
According to the question, New number
= Original number + 27
\Rightarrow10x+\left(9-x\right)=10\left(9-x\right)+x+27⇒10x+(9−x)=10(9−x)+x+27
\Rightarrow10+9-x=90-10x+x+27⇒10+9−x=90−10x+x+27
\Rightarrow9x+9=117-9x⇒9x+9=117−9x
\Rightarrow9x+9x=117-9⇒9x+9x=117−9
\Rightarrow18x=108⇒18x=108
\Rightarrow x=\frac{108}{18}=6⇒x=18108=6
Hence, the 2-digit number = 10(9-x)+x = 10(9-6)+6 = 10 x 3 + 6 = 30 + 6 = 36