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Question

The sum of the digits of 2 digit # is 12. If the units is 2 more than the tens digit. Find the numbers...

Please explain completely...

Answer 1

Let the 2 digit no. be x+y
so, x + y = 12

[x is the ten digit no. while y is the unit digit no.]

and y = x + 2

Sub the value of y in "x + y = 12"
=> x + x + 2 = 12
=> 2x + 2 = 12
=> 2x = 10
=> x = 5

and y = x + 2
hence y = 7

Therefore the no. is 57

Answer 2

let the number be 10x + y, x being the 10s digit and y being the unit's
now, x+y = 12 ---(1)
and y = x+2 => x-y = -2---- (2)
on solving (1) and (2).. we get
x=5 and y= 7, hence the number is 57

Answer 3

let x be the tens and y the units
x+y=12 and
y-x=2
or
x=y-2 plug this into first equation

y-2+y=12

2y=14
y=7 using x= y-2 x=7-2
x=5

the number is 57