Answer:
Find the median of this data
21+23+60+60+50+54+54+59+26+15+43+15=480/ 12 = 40
Now the median should be 50 so take 50 - 40 = 10
The missing number from the data is 10
Cost of fuel = 30% of $400 000 = 30/100 x 400000 = $120 000
Fuel amount = $120 000/$1.5 = 80 000 liters
new cost of fuel = 80000 x $1.6 = $144 000
increase in cost = 144000 - 120000 = $24000
So the increase in petrol price increases the operating cost by $24000