#### Answer

a. 257.49 million
b. 1997
c. 2009

#### Work Step by Step

a. t=1993-1990=3
$P=2.57(3)+249.78$
$P=7.71+249.78$
$P=257.49$
b. P=270
$270=2.57(t)+249.78$
$270-249.78=2.57(t)$
$20.22=2.57(t)$
$20.22\div2.57=t$
$t=7.86$
1990+7.86=1997.86 or 1997
c. P=300
$300=2.57(t)+249.78$
$300-249.78=2.57(t)$
$50.22=2.57(t)$
$50.22\div2.57=t$
$t=19.54$
1990+19.54=2009.54 or 2009