10. The diagram shows a rhombus formed by joining each vertex of a square to the midpoint of a side of the square.
What fraction of the area of the square has been shaded?
12. The pupils in my class work very quickly. Jasleen answers four questions every $30$ seconds and Ella answers five questions every $40$ seconds.
Last week, Jasleen took exactly $1$ hour to answer a large set of questions.
How many minutes more than Jasleen did Ella take to answer the same set of questions?