a level biology question

https://imgur.com/a/uPcIrD0
helpppp ive tried everything i can think of

mark scheme:
Answer in range 0.07 to 0.09 = 2 marks;; 2. Answer in range 9.97 to 12.2
OR
Shows division by 140 or 20 x 7 = 1 mark;

oops didnt mean to put this in the maths section but it's not really biology it's more maths anyway

2.4g = control plot in soil with normal phosphate concentration from the graph
e^2.4 = 11.02...
20 weeks = 140 days
11.02.../140 = 0.08

2.4g = control plot in soil with normal phosphate concentration from the graph
e^2.4 = 11.02...
20 weeks = 140 days
11.02.../140 = 0.08

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