so since 2/5 of the washing machines have been sold that means 3/5 remain in the store
first find the number of washing machines that were in the store before any were sold
X is the number of washing machines in the store before selling
18=(3/5)X
18/(3/5)=X
X=18*(5/3)
X=30
so at the beginning there were 30 machines
then multiply the percent sold (2/5) by the number at beginning to find the number sold
(2/5)*30=12
so 12 machines were sold
to find the cost per machine divide the total price by number of machines sold so
$3840/12= $320
so the answer is $320 per machine
