Answer
In $1950,\ \quad 355$ parts per million
In $2000,\ \quad 377$ parts per million
In $2050,\ \quad 400$ parts per million
In $2100,\ \quad 425$ parts per million
Work Step by Step
In 1950, $\quad t=200$ (years after 1750)
In $1950,\ \quad C(200)=280e^{0.00119(200)}\approx 355$
In $2000,\ \quad C(250)=280e^{0.00119(250)}\approx 377$
In $2050,\ \quad C(300)=280e^{0.00119(300)}\approx 400$
In $2100,\ \quad C(200)=280e^{0.00119(200)}\approx 425$
