A bookseller sells Mathematics and English books. If 30 customers brought Mathematics books, 20 customers brought English books and 10 customers buy the two books, how many customers has he altogether?

29. If $X=\{{{n}^{2}}+1:n=0,2,3\}$and $Y=\{n+1:n=2,3,5\}$ find $X\cap Y$

27.  In a basket, there are 6 grapes, 11 bananas and 13 oranges. If one fruit is chosen at random, what is the probability that the fruit is either a grape or a banana?

In how many ways can 6 subjects be selected from 10 subjects for an examination?

A senatorial candidate had planned to visit seven cities prior to a primary election. However, he could only visit four of the cities. How many different itineraries could be considered?

 The histogram above represented the weight of students who travelled out of their school for an examination. How many people made the trip.

The pie chart above illustrates the amount of private time a student spends in a week studying various subjects. Find the value of k

Evaluate $\int{\sin 3xdx}$

The slope of the tangent to the curve $y=3{{x}^{2}}-2x+5$ at the point (1,6) is