Bryn has a stack of photos measuring 12cm wide and 16cm high. He wants to display them on a large rectangular poster in such a way that all photos are equally spaced on each side, including at the edges of the poster, as illustrated.

1.. Bryn wants to display 9 photos (with longer side vertical) in 3 rows of 3 photos each with 2cm spacing around each photo. What are the dimensions of the poster?

2. Bryn wants to display 24 photos (with longer side vertical) with 2cm spacing around each photo. He wants more columns than rows of photos. Find the smallest poster area that is needed.

3. Bryn wants to display 18 photos in 3 rows of 6 photos each with 3cm spacing around each photo. The photos may all be displayed in portrait orientation (longer side vertical) or in landscape (longer side horizontal). Which orientation uses the lesser poster area?

4. Bryn wants to display 24 photos (with longer side vertical) in 6 rows of 4 photos each with equal spacing around each photo. He has a poster that is 62 cm wide and 120cm high. He wants to use the full width of the poster but is prepared to trim some of its height to achieve the equal spacing. How much of the poster does he need to trim?

Please provide working out for all the questions. Thanks.