Number one is c. It should take her about nine days
The answer is c = .6x + 5
In order to find the equation, note that the price per pound is contingent upon the weight in x. Therefore, we can multiply the two together.
We also need to add the constant, which is 5.
40g+300 is less than or equal to 5000
g is less than or equal to 117.5
So that is 117 guests max can be invited
Lets look at the number. 76.78. In each of the different place holders the number is higher than 5. Lets do some examples. 74 rounded to the nearest whole number is going to be 70. 76 rounded to the whole number will be 80. The .78 in your question also contributes.
Answer: 80