Foundation January 2021 Paper 1 Q5
5 A sequence of shapes is made by shading squares on a square grid.
(a) On the grid, draw Shape number 4 (1)
(b) Complete the table. (1)
| Shape number | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Number of shaded squares | 5 | 9 | 13 |
(c) Find the number of shaded squares in Shape number 8 (1)
(d) Explain why no shape in the sequence is made by shading exactly 50 squares. (1)
| Scheme | Marks |
|---|---|
 Answer: Correct shape | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| 17, 21 | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| 33 | B1 |
| (1) |
Notes
B1: cao
| Scheme | Marks |
|---|---|
| The numbers of shaded squares are odd numbers | B1 |
| (1) | |
| (4 marks) |
Notes
B1: Accept e.g. 50 is an even number
or the sequence is all odd numbers
or 49 is in the sequence so 50 can't be as it's only one more
or 53 is the next number after 49 or 49 and 53 are in the sequence (so not 50)
or nth term is \(4n + 1\) and for 50 \(n\) = 12.25 / not an integer