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Grade 11Magical Mathematics[Interesting Approach]

a number consist of two digits whode sum is 15 . if 9 is added to the number then the digits change places find the number​

Profile image of Ayush
5 Years agoGrade 11
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1 Answer

Profile image of Himanshu saxena
5 Years ago
Lets, say the original number has “x” at the 10th place and “y” at the one’s place,
thus the number can be written as (10x + y)
also, (x + y = 15; given) …... Eq(i)
also, (10x + y +9 = 10y + x) ….. Eq(ii)
Solving Eq(ii) gives us,
(x – y = -1) ...... Eq(iii)
Adding, Eq(i) and Eq(iii), we get x= 7 thus, y=8
Hence, the original number is (10 * 7 + 8 = 78).
 
The original number is 78.

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