ibm - the average number of visitors of a library in the first 4 days of a week was 58 the average for the 2nd 3rd 4th and 5th days was 60if the number of visitors on the 1st and 5th days were in the ratio 78 then what is the number of visitors on the 5th day - skillgun

Assume the number of visitors be x
Ratio of 1st and 5th day is 7:8
Number of visitors on 1st and 5th day be 7x and 8x.
Average number of visitors in the first 4 days = 58
i.e., (M + T + W + TH)/4 = 58
Then (7K + T + W + TH) = 232
(7K + T + W + TH) = 232 ...(1)
Average visitors on 2nd, 3rd, 4th and 5th days = 60.
(T + W + TH + F)/4 = 60
(T + W + TH + 8K) = 60 x 4 = 240
(T + W + TH + 8K) = 240 ...(2)
Subtracting (1) from (2) we get,
8K - 7K = 240 - 232
K = 8
Therefore visitors on 5th day = 8(8) = 64
Hence the answer is 64.