He has the biology quiz every 5 days . The online maths quiz is every 4 days. June 6 both quiz were taken.
Therefore,
[tex]\begin{gathered} The\text{ first term is 6} \\ \text{for the biology the sequence will be } \\ 6,11,16,21,26,31 \\ \text{For the math the sequence will be} \\ 6,10,14,18,22,26 \\ Both\text{ quiz will be due on june 26} \end{gathered}[/tex]