Problema Solution
the sum of the digits of a three-place number is 16.
if the digits are reversed and the resulting number is added to the original,
number the sum is 1049.
if the resulting number is subtracted from the original number the difference
is 297.
what are the numbers?
Answer provided by our tutors
Lets assume the number is xyz
That can also be written as 100*x +10*y + z
Now the sum of the digits of a three-place number is 16 i.e. x+y+z = 16 ......(i)
and if the digits are reversed and the resulting number is added to
the original, number the sum is 1049.
This can be written as xyz + zyx =1049 or
100*x +10*y + z + (100*z+10*y+x) = 1049 or
101*x + 20*y + 101*z = 1049 .............(ii)
Again if the resulting number is subtracted from the original number
the difference is 297.
This can be written as xyz - zyx =297or
100*x +10*y + z - (100*z+10*y+x) = 297 or
99*x - 99*z = 297 ......(iii) or
99* (x-z) = 297 i.e. x-z = (297/99)
=> x-z = 3 or x = z+3
Replacing the value of x in (i) and (ii)
x+y+z = 16 becomes z+3+y+z = 16 or y+2z = 13 or
y = 13 - 2*z.......................(iv)
101*x + 20*y + 101*z = 1049 becomes 101*z + 303 + 20*y + 101*z = 1049 or
=> 202*z+20*y = 746
Using value of y from (iv)
202*z + 20* (13-2*z) = 746 or
162*z + 260 = 746
z= (746-260)/162
z = 486/162 =3
now we know x = z+ 3 and y = 13-2*z
so
x = 6
y = 7
z = 3
XYZ = 673
Check -
673+376 = 1049
673-376 = 297