To do this you must divide 800/10 = 80
The constant term is 7. this is because x and y are unknowns and change depending on the other. As 6x^3y will change depending on what x or y is so will: 8x^2 and 5x therefore 7 is the constant term.
Choice A would be true if it was for 8 years, and not 8 months. The value of t is in years. We would need to convert 8 months to years like so
12 months = 1 year
1 month = 1/12 of a year
8 months = 8/12 of a year
8 months = 2/3 of a year after dividing both parts by 4
So we'll go for choice B as the final answer
The easiest way to do it is to make a ratio. 45% is equal to .45 and 35% is .35.
.45/x=.35/5400
Now you cross multiply and divide to find the previous duty.
5400*.45=2430
2430/.35=6942.86