Latest CAT Aptitude Question SOLUTION: How many two digit numbers increases by 18 when their digits are reversed?

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How many two digit numbers increases by 18 when their digits are reversed?

Asked In CAT Devendra Marghade (12 years ago)

Solved Sanjana Patnaik Read Solution (6)

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Read Solution (6) :

Sanjana Patnaik  (12 years ago)

Let the two digit No. be xy(tens digit"x" and Units digit"y")
then, the value of the two digit is 10x+y
When the same is reversed, the value of the digit is 10y-x
As per the condition:
(10y-x)-(10x+y)=18
which implies, 9(y-x)=18
y-x=2
Thus, the units digit is more than the Tens digit
Thus, the numbers are:
13,24,35,45,57,68,79( seven No. of two digits)

Is this solution Helpfull? Yes (4) | No (1)  

Vignesh  (12 years ago)

7 two digits numbers increases by 18 when their digits are reversed.

They are,

13, 24, 35, 45, 57, 68, 79,

Is this solution Helpfull? Yes (3) | No (1)  

Sneha paliwal  (12 years ago)

ans = 13,24,35, 46, 57,68,79. (total 7 case)
let no. denoted as 10y+1x
now reverse the no =10x+1y
now difference b/w them (10y+1x)-(10x+1y)=18
that is 9y-9x=18
y-x=2 that equation shows that the in two digit no the diffrence bw x and y value should be two therefore no, are=13, 24,35,46,57,68,79.
total 7 case.

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Sanjana Patnaik  (12 years ago)

There was a typographicl mistake:
Instead of putting 10y+x, I had put 10y-x

Is this solution Helpfull? Yes | No (1)  

Manju Raghavendra  (12 years ago)

we can calculate it directly there are 7 numbers they are 13, 24 ,35, 46, 57, 68, 79.

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manudixit  (12 years ago)

7 digits
13, 24, 35, 46, 57, 68, 79

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