Q. 10

A number consists of two digits whose sum is 10. If 18 is subtracted from the number, its digits are reversed. Find the number.

Class 10th RS Aggarwal - Mathematics 3. Linear Equations in Two Variables

Answer :

Let us assume the ones digit be x and the tens digit be y

According to the question, we have

x + y = 10 …(i)

(10y + x) – 18 = 10x + y

x – y = – 2 …(ii)

Now, adding (i) and (ii) we get:

2x = 8

Now by putting the value of x in (i), we get

4 + y = 10

y = 10 – 4

y = 6

Hence the required number is 64

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