Answer:
The total number of guests that were at the wedding was 276.
Explanation:
Let the total number of guests at the wedding be, N.
The meal options are:
Beef, Chicken and Vegetarian.
It is provided that:
Proportion of guests who chose beef is,
.
Proportion of guests who chose chicken is,
.
According to the laws of probability, the sum of the probabilities of all the events of a sample space is 1.
Then the sum of probability of guests selecting beef, chicken or vegetarian should also be 1.
Compute the proportion of guests who chose vegetarian as follows:
P (Vegetarian) = 1 - P (Beef) - P (Chicken)



So, the proportion of guests who chose vegetarian was
.
It is also provided that the number of guests who chose vegetarian was 69, i.e.
of N = 69.
Compute the value of N as follows:



Thus, the total number of guests that were at the wedding was 276.