Answer:
5/28
Step-by-step explanation:
1/1 represents the whole amount of tickets.
4/7 are sold on Thursday.
an additional 1/4 are did on Friday.
fraction of available tickets on Saturday are therefore
1/1 - 4/7 - 1/4 = 4/1 - 16/7 - 1/1 = 28/1 - 16/1 - 7/1 = 5/1
that means out of 28 equal parts of the total number of tickets 16+7 = 23 parts have been sold.
so, there are only 5 out of the total 28 parts available on Saturday, and the fraction of available tickets is therefore 5/28.
we could have also tried to bring both fractions to the same denominator, and found that this is 28.
and then
4/7 + 1/4 = 4/4 × 4/7 + 7/7 × 1/4 =
= 16/28 + 7/28 = 23/28
and the whole is 28/28.
so we have 28/27 - 23/28 = 5/28 left.
surprise, surprise, it is the same result ...