if$($age $<=2)$

totalAirfare $=0$;

$//$ if age is greater than $60,$ then there is $290$ base cost.

else if$($age $>=60)$

totalAirfare $=290$;

$//$ otherwise base cost is $300$$$.$

else

totalAirfare $=300$;

$//$ if total number of carryOn $=1,$ then extra charge of $$10.$

if$($carryOn $>0)$

totalAirfare $=$ totalAirfare $+10$;

$//$ if checkedBags $=2,$ then add $$25$ to totalAirfare.

if$($checkedBags $==2)$

totalAirfare $=$ totalAirfare $+25$;

$//$ if number of checkedBags $>2,$ then

$//$ first add $$25$ for second bag and then add extra $$50$ for each bag.

else if$($checkedBags $>2)$

totalAirfare $=$ totalAirfare $+25+50*($checkedBags $-2)$;