The ratio of two two-digit numbers, which have the same digits but in reverse order, is 7 : 4. What is the maximum possible difference between the two numbers?
a. 9 b. 18 c. 17 d. 36 e. 45

• d. 36
  
  If two digit numbers are 10x+y and 10y+x then (10x+y)/(10y+x)=7/4, x=2y
  For x=1,y=2,
  x=2, y=4
  x=3, y=6
  x=4, y=8
  So numbers can be formed as 21 & 12, 42 & 24, 63 & 36, 84 & 48
  Hence maximum possible difference between two numbers is 84-48=36
• 8 years agoHelpfull: Yes(1) No(0)
• a. 9
  the smallest digit that can be multiplied in order to get a number that'll have the ratio as 7:4 is 3.
  21-12=9
  So, the answer is 9
• 8 years agoHelpfull: Yes(0) No(0)
• I didn't notice the word maximum! Sorry :( then the answer has to be 36.
• 8 years agoHelpfull: Yes(0) No(0)
• d.12*7:12*4=84:48
  therefore the difference is 36
• 8 years agoHelpfull: Yes(0) No(0)
• option check: the question mentioned maximum possible difference therefore start from (e)
  (e) given 7:4 => 7x = 4x
  7x - 4x =45
  3x=45
  x=15
  therefore 7*15=105(this is three digit => not option (e))
  (d) 3x= 36 => x=12
  7*12=84
  4*12=48
  Both satisfying the question so option (d)
  and therefore don't check a,b,c as they are less than 36
• 8 years agoHelpfull: Yes(0) No(0)
• To get the maximum difference the two didgit numbers should be large satisfying the given condition. So the ans is 84:48=7:4 and the difference is 36
• 8 years agoHelpfull: Yes(0) No(0)