Answer:

a) 1999

b) 2013

Explanation:

$\large \bf{p = \frac{184.64 + 0.7524 {t}^(2) }{1 + 0.0028 {t}^(2) } }$

$\bf \longrightarrow{200= \frac{184.64 + 0.7524 {t}^(2) }{1 + 0.0028 {t}^(2) } }$

$\bf \longrightarrow{200 + 0.56 {t}^(2) = 184.64 + 0.7524 {t}^(2) }$

$\bf \longrightarrow{0.7524 {t}^(2) - 0.56 {t}^(2) = 200 - 186.64}$

$\bf \longrightarrow{0.1924 {t}^(2) = 15.36}$

$\bf \longrightarrow{ {t}^(2) = 79.83}$

$\bf \longrightarrow{t = 8.93}$

$\bf \longrightarrow{t = 9 \: years}$

$\bf \longrightarrow{ \boxed{ \sf{T \: = 1990 + 9 = 1999}}}$

$\bf \longrightarrow{266= \frac{184.64 + 0.7524 {t}^(2) }{1 + 0.0028 {t}^(2) } }$

$\bf \longrightarrow{266 + 0.7448 {t}^(2) = 184.64 + 0.7524 {t}^(2) }$

$\bf \longrightarrow{0.7524 {t}^(2) - 0.7448 {t}^(2) = 266 - 184.64}$

$\bf \longrightarrow{0.0076 {t}^(2) = 81.36}$

$\bf \longrightarrow{ {t}^(2) = 529}$

$\bf \longrightarrow{t = 23 \: years}$

$\bf \longrightarrow{ \boxed{ \sf{T \: = 1990 + 23 = 2013}}}$