Answer :
Sum and difference problem, where difference = larger number - smaller number.
The larger number is (sum+difference)/2.
The smaller number is (sum - difference)/2
Therefore the dryer costs (911+39)/2=475
The washer costs (911-39)/2=436
The larger number is (sum+difference)/2.
The smaller number is (sum - difference)/2
Therefore the dryer costs (911+39)/2=475
The washer costs (911-39)/2=436