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