Plz.give detailed answer because tomorrow my maths exam is there.☺️☺️☺️☺️☺️☺️☺️☺️☺️
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Plz.give detailed answer because tomorrow my maths exam is there.☺️☺️☺️☺️☺️☺️☺️☺️☺️
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Let the digit at tens place be x and the digits at units place be y.
Hence, the number formed = 10x + y.
On interchanging the new number is 10y + x.
Now,
Given that sum of two digit number is 15.
= > x + y = 15 ------- (1)
Given that number formed by interchanging the digits exceeds number by 9.
= > 10y + x = 10x + y + 9
= > 10y + x - 10x - y = 9
= > 9x - 9y = - 9
= > x - y = -1 ------ (2)
On solving (1) & (2), we get
= > x + y = 15
= > x - y = -1
--------------
2x = 14
x = 7.
Substitute x = 7 in (1), we get
= > x + y = 15
= > 7 + y = 15
= > y = 8.
Hence, the original number = 10x + y
= > 10(7) + 8
= > 70 + 8
= > 78.
Therefore, the original number = 78
Hope this helps!