What is the average rate of the reaction

Question

A+3B—>2C

[A]/M Time /s

0.80 0

0.40 15

0.20 30

What is the average rate of the reaction with respect to A over the first 15 seconds of the reaction in M / s ? ( Express your answer as a decimal, not scientific notation and be mindful of significant figures)

Answer 1

Average rate of change of A over the first 15 sec = 0.40 M - 0.80 M /15 sec = -0.027 M/s