Cumulative Frequency (Interquartile Range)

Hi,

I understand what an interquartile range is, however when I was asked to answer the following question I did not know why I got it wrong:

" A box contains 100 cards. Each card has a number between one and six written on it. The following table shows the frequencies for each number.

Number: 1, 2, 3, 4, 5, 6

Frequency: 26 10 20 4 29 11

Cumulative F: 26 36 56 60 89 100

So what I did was worked out, the UQ which was 75 and took the LQ away from it which was 25, leaving 50. The number 50 corresponded to the the number 3 which I thought was correct, however the actual answer is 4. (NB: a graph was not supposed to be drawn).

Please tell me where I went wrong and why is 4 the answer.

Thanks

p.s sorry for the badly drawn table.