Question

The sum of the digits of a 2-digit number is 7. If the digits are reversed, the new number increased by 3
less than 4 times the original number. Find the original number
​

Answer 1

Explanation:

Let tens place be x and ones place be y

therefore, the no is=10x+y

In Ist condition,

x+y=7

the no obtained by reversing its digits=10y+x

In 2nd condition,

4(10x+y)-(10y+x)+3=0

or, 40x+4y-10y-x+3=0

or, 39x-6y+3=0

or, 39x-6y=-3

Now solving equation i and ii,we get:

6x +6y=13

39x- 6y=-3 [by cancelling the like term]

6x+39x=13-3

or, 45x=10

or, x =10/45

or, x =2/9

Now putting the value of x=2/9 in equation i, we get:

x+y=7

or, 2/9+y=7

or, y = 7-2/9

or, y = 63-2/9

or, y = 61/9

therefore,

Ans: x=2/9

y=61/9 or 6 whole 7/9

Hope it helps you!!