In a certain school, 80 pupils study both Biology and History, 35 study neither subject, 45 study only Biology and 60 study only History. Find the probability that a randomly selected pupil

a) studies at least one of the two subjects
b) studies History

Does the point (1, sqrt 7) lie on circle shown.

Evaluate the expression. (9 + 5)(3 + 2)0

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex