For eg \(40 - 24 = 16\) condone \(24 - 40 = 16\) or \(24 - 40 = -16\)
Condone incorrect use of equals sign eg \(1.2 \times 20 = 24 + 16 = 40\) or \(1.2 \times 20 = 24 - 40 = 16\)
B1
Correct response with irrelevant work
B1
16 from two different ways with one way incorrect is choice eg \(1.2 \times 20 = 24\) and \(40 - 24 = 16\) and \(20 \div 1.2 = 16\)
B0
Mark scheme (b)
Answer
Mark
Comments
3
B1
Correct method for gradient eg \(\dfrac{40 - 16}{15 - \text{their } 3}\) or \(\dfrac{24}{12}\)
M1
oe eg \(\dfrac{30 - 25}{10 - 7.5}\) or \(\dfrac{10}{5}\) or \(40 - 38\)
2
A1ft
correct or ft their 3
Additional guidance
Note that their 3 can be used to work out the rate but does not have to be
Values seen on graph must be used correctly eg 24 and 12 seen on the graph is M0 unless subsequently used correctly in attempt to work out the gradient
A1ft answers must be to 1 dp or better eg 3.5 \(\dfrac{40 - 16}{15 - 3.5}\) 2.1 (accept 2.08…)
B0 M1 A1ft
After B0 the method may be implied (use \(\dfrac{40 - 16}{15 - \text{their } 3}\) to check) eg 6 2.7 (accept 2.66…)
B0 M1A1ft
If the report is blank, 3 and 2 must be unambiguously identified in working to be acceptable
