La taille d'un nénuphar double chaque jour. Au bout de 40 jours, il a recouvert tout l'étang. Au bout de combien de jours avait-il recouvert la moitié de l'étang?

c) \( 8+(-18): 3= \)

\( 37 ; 33 ; 29 ; x ; 21 ; \ldots \). Write down the value of \( x \). Determine the \( n^{\text {th }} \) term of the number pattern. Determine the \( 15^{\text {th }} \) term of the sequence. Which term is the first to have a negative value.

10. A girl swims 400 m in still water and then returns to the initial point (from where she started) in 20 minutes. Determine the speed of the girl. 11. A man is running at a speed of \( 3 \mathrm{~m} / \mathrm{s} \) and covers some distance in 15 sec . Find the time taken by his pet dog to cover the same distance at a speed of \( 10 \mathrm{~m} / \mathrm{s} \).

\( ( 7 \times 5 ) \quad \bmod 6 \)

Find \( \frac{5}{6}-\left(-\frac{3}{4}\right) \). Write your answer as a mixed number in simplest form.