Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
Mary stores her digital images on her computer in three separate folders called ‘Family’, ‘Holiday’ and ‘Friends’. Her family folder has 3 images, her holiday folder has 4 images and her friends folder has 8 images. Every image is different.
(i)[3]
Find how many ways she can line up these 15 images in a row across her computer screen if she keeps the images from each folder together.
(ii)[2]
Find the number of different ways in which Mary can choose 6 of these images if there are 2 from each folder.
(iii)[4]
Find the number of different ways in which Mary can choose 6 of these images if there are at least 3 images from the friends folder and at least 1 image from each of the other two folders.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Three factorials multiplied together” …