Sounds that you have several answer choices. If that's the case, you need to share those choices. All of them are probably inequalities.
The percentage decrease is 60% decrease because it changed by 81 and 81 is 60% of 135
Answer: c. 150g of sugar dissolved in 300ml water
Step-by-step explanation:
The concentration of sugar syrup will decide which syrup is sweetest. Concentration is defined as the amount of solute dissolved per unit volume of solution.
a) 50g of sugar dissolved in 150ml water

b) 100g of sugar dissolved in 500ml water

c) 150g of sugar dissolved in 300ml water

d) 250g of sugar dissolved in 1000ml water

Thus 150 g of sugar dissolved in 300ml water has highest concentration and is sweetest.
The correct answer is 1 mm Hg per year.