Question

the sum of the digits of a two- digit number is 7. If the digits are reversed the number is increased by 27. What is the number?

Answer 1

let the number be xy. Then x+y=7 and 10y+x=10x+y+27. So just solve this system of two equations

Answer 2

It makes sense now. I just couldn't get it set up. Thank you.

Answer 3

Let first digit be x.Then,

second digit of the number = (7-x)
Original number=10*(7-x)+x=70-10x+x=70-9x
reversed number=10*x+(7-x)=10x+7-x=9x+7

A/q,
=> (70-9x)+27=9x+7

solve for x now :)

Answer 4

sum of digits is x+y=7 -equation (1)
the number will be 10x+y
if we chnge the place of digits the nmber increases by 27 so
10x+y=10y+x-27
=> 9x-9y=-27
=> x-y=-3 -equation(2)
sum up equation 1 nd 2
=> 2x=4
x=2
putting value of x in eq(1)
y=5

so the number will be
10(x)+y
=20+5
=25
..............
now its digit sum is 2+5=7 nd change its digits place it will be 52 which is 27 greater than 25...

Answer 5

@khurramshahzad is right also. only difference is that he did the solution using two variables & I did with one variable :)

Answer 6

yup

Answer 7

:)

Answer 8

your problem has 6 answer , I list in a draw