Probability Short Problems - Age 11-14


This is part of our collection of Short Problems.

You may also be interested in our longer problems on Probability - Stage 3.

Collecting Marbles

Age 11 to 14 Short Challenge Level:

A bag contains coloured marbles. How many need to be taken out to ensure that at least three are of the same colour?

Strange Dice

Age 11 to 14 Short Challenge Level:

If two of these unusually numbered dice are thrown, how many different sums are possible?

Half and Half

Age 11 to 14 Short Challenge Level:

Two of the four small triangles are to be painted black. In how many ways can this be done?

Tying the Rope

Age 11 to 14 Short Challenge Level:

What is the probability that two pieces of rope are tied together, when Pat ties two loose ends together?

Satnav Dilemma

Age 11 to 14 Short Challenge Level:

How many routes are there in this diagram from S to T?

Would You Like a Jelly Baby?

Age 11 to 14 Short Challenge Level:

What is the smallest number of jelly babies Tom must take, to be certain that he gets at least one of each flavour?

Birthday Party

Age 11 to 14 Short Challenge Level:

The 30 students in a class have 25 different birthdays between them. What is the largest number that can share any birthday?

School Dinners

Age 11 to 14 Short Challenge Level:

Our school dinners offer the same choice each day, and each day I try a new option. How long will it be before I eat the same meal again?

Takeaway Time

Age 11 to 14 Short Challenge Level:

Pizza, Indian or Chinese takeaway? If everyone liked at least one, how many only liked Indian?

One or Both

Age 11 to 14 Short Challenge Level:

Problem 1 was solved by 70% of the pupils. Problem 2 was solved by 60% of them. Can you work out how many pupils took the exam?

Perfect Score

Age 11 to 14 Short Challenge Level:

Can you work out how many children answered all the questions correctly?

Monkey Puzzle

Age 11 to 14 Short Challenge Level:

What is the probability that all three monkeys left the cafe wearing the wrong hats?

Clubs

Age 11 to 14 Short Challenge Level:

How many students are in the maths club and the science club?

Fair's Fair

Age 11 to 14 Short Challenge Level:

Can you design a die which rolls 'fairly' against mine?

Counting Kangaroos

Age 11 to 14 Short Challenge Level:

Can you work out how many kangaroos Rachel draws in one colour?

Almost Constant Digits

Age 11 to 14 Short Challenge Level:

Consider a 10-digit number which contains only the numbers 1, 2 or 3. How many such numbers can you write so that every pair of adjacent digits differs by 1?

Counting Socks

Age 11 to 14 Short Challenge Level:

Can you work out the smallest number of socks Rachel needs to take out of the box to be guaranteed a pair?

Rain

Age 11 to 14 Short Challenge Level:

How many dry days did Aisha have on her holiday?