Which two signs need to be interchanged to make the given equation correct?
$$16 + 27 \div 3 - 9 \times 12 = 85$$

Option (a) $$+, \div$$

$$16 \div 27 + 3 - 9 \times 12 = 85$$

In this the values will be in fraction which is not possible as per the given equation. So this will not be the correct answer.

Option (b) $$-, \times$$

$$16 + 27 \div 3 \times 9 - 12 = 85$$

$$16+\frac{27}{3}\times9-12 = 85$$

$$16 + 27\times3 - 12 = 85$$

$$16 + 81 - 12 = 85$$

85 = 85

The given equation is satisfied. So this will be the correct answer.

Option (c) $$-, +$$

$$16 - 27 \div 3 + 9 \times 12 = 85$$

$$16 - 9 + 108 = 85$$

$$115\ne85$$

In this the given equation is not satisfied. So this will not be the correct answer.

Option (d) $$\times, \div$$

$$16 + 27 \times 3 - 9 \div 12 = 85$$

In this the values will be in fraction which is not possible as per the given equation. So this will not be the correct answer.