Final answer:
The probability that Melissa picks either a cheese biscuit or a beef biscuit is 4/7 (or approximately 0.57).
Step-by-step explanation:
To find the probability that Melissa picks either a cheese biscuit or a beef biscuit, we need to count the total number of cheese and beef biscuits and divide it by the total number of biscuits in the bag.
There are 2 cheese biscuits and 2 beef biscuits, so the total number of cheese and beef biscuits is 2 + 2 = 4.
The total number of biscuits in the bag is 7.
Therefore, the probability that Melissa picks either a cheese biscuit or a beef biscuit is 4/7 (or approximately 0.57).