Q. A two digit number is greater by 4 than 8 times the sum of the digits. If 7 times the tens place digit is subtracted from the given number, the new number obtained is that obtained by interchanging the digits of the original number. Find the given two digit number.

• ans 92
  Let the two digit number be xy i.e. 10x+y
  Given two digit number is greater by 4 than 8 times the sum of the digits
  10x+y=8(x+y)+4---(1)
  Given 7 times the tens place digit is subtracted from the given number, the new number obtained is that obtained by interchanging the digits of the original number =) 10x+y-7x=10y+x---(2)
  Solving (1) & (2) we get x=9,y=2
  Therefore required two digit number=92
  
  
• 11 years agoHelpfull: Yes(40) No(0)
• Let the two digit number be 10x+y.
  therefore from the first line of the question we can have :-
  10x+y=8(x+y)+4.
  solving this we have 2x-7y=4. --------------(1)
  Now the second line of the question states that:-
  10x+y-7x=10y+x
  solving this we have 2x=9y. ----------------(2)
  Substituting equation (2) in equation (1) and solving it will give me the value of y to be 2. and then putting the value of y in equation (2) we get x to be 9.
  therefore the number is:
  92
• 11 years agoHelpfull: Yes(1) No(0)
• 7x=10y+x
  not satisfy by x=9,y=2
  so 92 not correct ans
  
• 11 years agoHelpfull: Yes(0) No(13)
• 8(x+y)=10x+y-4
  8x+8y-10x-y+4=0
  -2x+7y=-4
  2x-7y=4----(1)
  10x+y-7x=10y+x
  3x-x+y-10y=0
  2x-9y=0-----(2)
  solving equation (1) and (2)=>x=9 and y=2
  thus, given 2 digit no.=90+2=92
• 11 years agoHelpfull: Yes(0) No(0)
• let the number xy.
  10x+y-8x-8y=4
  2x-7y=4.....eq 1
  10x+y-7x=10y+x
  2x-9y=0....eq2
  by solving eq 1&2 we get y=2 and x=9
  then the 2 digit num=92
  
• 11 years agoHelpfull: Yes(0) No(0)