A book seller sells Mathematics and English books. If 30 customers buy Mathematics books, 20 customers buy English books and 10 customers buy the two books. How many customers has he altogether?

Similar Questions

Evaluate $\int 2(2x - 3)^{\frac{2}{3}} \mathrm d x$ ...

Which of the following fractions is less than one-third? ...

The parallel sides of a trapezium are 13cm and 7cm. If the area of the trapezium is 50cm2, find the ...

In 1984, Ike was 24 yrs old and his father was 45 yrs old. In what year was Ike exactly half his fat...

The ages of students in a small primary school were recorded in the table below. Age  5...

In one and a half hours, the minute hand of a clock rotates through an angle of ...

At what value of X does the function y = -3 - 2x + X2 attain a minimum value? ...

If the simple interest on a certain amount of money saved in a bank for 5 years at 2$\frac{1}{2}$%...

A cliff on the bank of a river is 300 metres high. if the angle of depression of a point on the oppo...

Find the value of y, if log (y + 8) + log (y - 8) = 2log 3 + 2log 5 ...