Answer: 17 010
If $24300 is the 100% (full price), then after year it would be 70% of that cost (because 100% decreases by 30% in a year). We can cross multiply the values:
$24300 100%
x 70%
so cross multiplying: 100 with x and 24300 with 70
-> 100x = 1701000
so the x will be 17010