Answer:
x= 3rd contest prize =$1800
the second contest prize is 80% of the third contest prize = 0.8x
the first contest prize is 60% of the second contest prize = 0.6*0.8x=0.48x
we know that x =$1800, we replace x to calculate how much Jason has won in total
1800+1800*0.8+1800*0.48=$4104