Consider the reaction: 2a(g)+b(g)→3c(g). when a is changing at a rate of -0.110m⋅s−1, how fast is c increasing?

From the reaction above, the rate is given by the following formula:
r = -(1/2) dA / dt = - dB / dt = (1/3) dC/ dt
Note that A and B charge is negative due to they decrease with time
given dA / dt = -0.110 M/s
hence dB / dt = -0.110 / 2 = -0.055 M/s
dC / dt = (-3/2) (-0.110) = 0.165 M/s 

The answer is b metal denting