There were 72 students in Class 3A and Class 3B altogether. If 2 students were transferred from 3B to Class 3A, Class 3A would have 8 more students than Class 3B. How many students were there in Class 3B at first ?

Paul and May had 210 marbles altogether. When Paul gave May 18 marbles, both of them had the same number of marbles. How many marbles did each of them have at first ?

Carton A and Carton B had 80 apples in all. When 15 apples were transferred from Carton A to Carton B, the two cartons had the same number of apples. How many apples were there in each carton at first ?

Van and An have 180 books altogether. Van has 12 more books than An. How many books does each of them have ?

Anna and Bella have 320 dollars altogether. Bella and Tom have 360 dollars in all. Tom and Anna have 240 dollars altogether. How much does each of them have ?

There are 120 books altogether on a bookshelf. The top shelf holds 11 more books than the middle one. The bottom shelf holds 5 books fewer than the middle one. How many books are there on each shelf ?

Aloy and Ben have 150 dollars altogether. Aloy’s mother gives him another 40 dollars and Ben spends 10 dollars on a book. Ben then has 10 dollars more than Aloy. How much money does each of them have at first ?

There are a total of 660 passengers on two ships. 30 passengers alight from Ship A and 70 passengers board Ship B. As a result, the number of passengers on the two ships becomes the same. How many passengers are there on each ship at first ?

In the final match of a basketball league, the team that wins two consecutive games will be the champion. Otherwise, the team that wins three games in total will win the title. How many possible ways can a team win ?

Mrs Clancy rings her students to inform them of the cancellation of a lesson. In the first minutes, she informs Abel. In the second minute, she informs Dian, and Abel in turn informs Chloe and so on. How many students are informed of the cancellation of the lesson in 5 minutes ?

In the figure below, how many triangles can be formed using any three points ?

A street has 12 lamp-posts. In an attempt to save energy, the City Planning Department decides that only 5 lamps should be turned on at any one time. In how many ways can this be done ?

Weights of 1 g, 5 g and 8 g are placed on a balance. How many different amounts of weight can the balancee measure ?

How many times does the digit “3” appear from numbers 1 to 2009 ?

How many different ways are there to pick three numbers with an even sum from 1, 2, 3, 4, 5 and 6 ? The order of the three numbers need not be considered

How many different ways are there to form a 3-digit number if the three numbers are chosen from 1, 2, 3, 4, and 5 ?

The sum of the digits of a 2-digit number is 9. How many such numbers are there ?

A circle that is adjacent to another is considered a pair. How many pairs of cirles are there in the figure below ?

The average age of Laura, Melissa and Nichola is 20 years. The average age of Robert, Melissa and Nichola is 18 years. How old is Robert if Laura is 32 years old ?

Jason’s grandfather is 70 years old and Jason is 10 years old. How many years old was his grandfather’s age 11 times his ?

The sum of Melissa and her parents’ ages is 81. Her father is as old as her mother. Her mother’s age is 4 times Melissa’s age. How old is each of them ?

Three years ago, the age of Ben’s father was 6 times Ben’s age. Their total age is 55 now. How old is Ben now ?

Seven years from now, Natalie’s age will be the same as Olivia’s age five years ago. The sum of their age is 34. How old are Natalie and Olivia now ?

Four years ago, the total age of Anne and her father was 37. Her father’s age is four times that of Anne now. How old is Anne’s father now ?

Rose is 8 years old. Her father is 34 years old. When will her father be thrice her age ?