Latest Elitmus Aptitude Question SOLUTION: the square of two digit number(ab) divided by half of itself resultant added by 18 then divided by 2 then we get reverse of original number(ba). how many combination of ab exist a)

• Placement Papers
• /
• Elitmus
• /
• Numerical Ability
• /
• Number System

Elitmus Question Papers:

(#M40157147) ELITMUS Numerical Ability question number system Keep an EYE

the square of two digit number(ab) divided by half of itself resultant added by 18 then divided by 2 then we get reverse of original number(ba). how many combination of ab exist
a) 9
b) 8
c) 7
d) 6

Asked In Elitmus ranjeet singh (7 years ago)

Unsolved Read Solution (10)

Is this Puzzle helpful?   (6)   (2) Submit Your Solution Number System

Read Solution (10) :

Aiman Shakeel  (7 years ago)

(((10a+b)^2)/(10a+b/2)+18)/2=10b+a.
Simplify the above equation.
The final equation will be a-b=-1
There will be 8 combinations of a &b which will satisfy this equation.
i.e.
a=1,b=2
a=2,b=3
a=3,b=4
a=4,b=5
a=5,b=6
a=6,b=7
a=7,b=8
a=8,b=9

Is this solution Helpfull? Yes (25) | No   

Sibabrat Swain  (7 years ago)

1- [{(ab)*(ab)}/{(ab)/2}+18]/2 = ba. this is the question .
2- we can re write the expression as ab+9 =ba (try to solve the question, it is too easy ).
3- you will get 8 no of combinations .(answer)
those are
12+9 =21
23+9=32
...
89+9=98
* you cant take 01+9 = 10 , because o1 is a single digit no .

Is this solution Helpfull? Yes (5) | No (3)  

saurav justin  (7 years ago)

b-a=1
so total possible combination will be 8 by using the digit 1 to 9

Is this solution Helpfull? Yes (2) | No   

ramakant  (7 years ago)

ans...8
let number is n.=ab
then n=10a+b..
reverse num=ba=10b+a.
now..((10a+b)^2/(10a+b)/2+18)/2=10b+a
=>(2(10a+b)(10a+b)/(10a+b)+18)/2=10b+a
=>(2(10a+b)+18)/2=10b+a
=>(10a+b)+9=10b+a
=>9a+9=9b
=>a+1=b.
and possible combination are..
a=1,b=2
a=2,b=3
a=3,b=4
a=4,b=5
a=6,b=7
a=7,b=8
a=8,b=9

Is this solution Helpfull? Yes (1) | No   

suvasree chatterjee  (7 years ago)

plz sm1 explain how this eq reduced to a simple form

Is this solution Helpfull? Yes | No   

Aditya Anil pole  (7 years ago)

@Sibabrat swain, your basics seem to be weak. For example take the second step:

2- we can re write the expression as ab+9 =ba (try to solve the question, it is too easy ).
Solution: ab+9=ba
ab+9-ba=0
ab-ba=-9
0=9
As ab and ba are the same numbers. You have to take 10a+b in the first step itself. ba is not the reverse of ab.
Suppose, a=9 & b=8. => ab=72 and ba=> 72 also.

Is this solution Helpfull? Yes | No (2)  

suvasree chatterjee  (7 years ago)

but in the Q it is writen that ba is rev of ab so we cant do ab-ba=0

Is this solution Helpfull? Yes | No   

gmswacc  (7 years ago)

Please tell the confirmed, verified and correct Answer, please comment on this fast

Is this solution Helpfull? Yes | No   

megha jain  (6 years ago)

ZAC
what is the cyclic method?

Is this solution Helpfull? Yes | No   

Deepak  (6 years ago)

the square of 2 digit number divided by half of itself= is equal to double of that number
and (double of that number+18)/2 = reverse that suggest they are combination of (x,x+1)
so
(12,23,34,45,56,67,78,89)= 8 combinations

Is this solution Helpfull? Yes | No   

Please Login to Read Solution.