Question

The sum of the digits of a 2-digit number is 7. If the digits are
reversed, the number formed is 9 less than the original number. Find
the number.​

Answer 1

Answer:

25

Step-by-step explanation:

Let the ones's digit =x.

So, sum of the digits =7

Tens's digit =7−x

Original no. =10(7−x)+x=70−10x+x=70−9x

Reversed no. =10x+7−x=9x+7

2(orig no) = reversed no. −2

2(70−9x)=9x+7−2

140−18x=9x+5

27x=135

x=5

Ten's digit =7−5=2

No. =25

Answer 2

Answer:

The number is 43.

Step-by-step explanation:

Suppose two digits of the number are - a and Therefore the number will be- ( 10a + b)

and also after reversing the digits of the number, it will become (10b+a)

now ,

sum of digits of number is

(a +b)=7 ........(i)

and

the number firm after reversing the digits will

become 9 less than the actual number

i.e.

(10b + a )=(10a + b) - 9 ..........(ii)

solving these two equation we get

a=4 and b=3

so the number will be (10a + b )= 10*4 + 3 = 43