1$^{st}$ April to 26$^{th}$ April $\longrightarrow$ 25 days
25 $\div$ 7=3 R4 $\longrightarrow$ 3 weeks 4 days
3 weeks after Monday $\longrightarrow$ Monday
4 days after Monday $\longrightarrow$ Friday

In the following sequence, 1,4,2,8,5,7,1,4,2,8,5,7,$\dots$ (a) What number is in the 50th position? (b) What is the sum of the first 63 numbers?

Every year around the Christmas period, Shaun and his church friends always go around carolling, at 7pm to 10pm each weekday night. If the group spends an hour for each house, inclusive of travelling time, and they started on Wednesday at 7pm, which day and at what time would they complete carolling for a street which contains 13 houses?