Question

Sum of 2 digit no is 7.If the digit are reversed the new number so formed increased by 27. Find the number

Answer 1

Answer:

25

Step-by-step explanation:

Sum of digits = 7

Let the digit at unit place be x.

So, digit at tens place = (7-x)          

Original No. = 10(7-x) + x

= 70-10x+x

= 70-9x         (i)

When the digits are reversed,

digit at units place = (7-x)

digit at tens place = x

New No. = 10(x) + (7-x)

= 10x + 7 -x

= 9x +7         (ii)

ATQ,

New Number - Original Number = 27

(9x+7) - (70-9x) = 27

9x+7-70+9x = 27

18x -63 = 27

18x = 27+63

18x = 90

x = 90/18

x = 5

Original Number = 70-9*5 from (i)               New Number = 9*5 + 7 from (ii)

= 70-45                                                                                 = 45+7  

= 25                                                                                       = 52    

Ans = 25  

Check,

New Number - Original Number = 27

52-45=27

L.H.S = R.H.S

Answer 2

Answer:

25

Step-by-step explanation:

Try 16, 25, 34.