Question 213985
Let K = Kirra's age, R = Reggie's age, and D = Delia's age.
{{{(K+R+D)/3 = 9}}}{{{1/3}}}
K = R+2 "Kirra is two years older than Reggie." Rewrite as K = R-2
R = 6D "Reggie is six times as old as Delia."
K+R+D can be expressed as:
{{{((6D-2)+6D+D)/3 = 9}}}{{{1/3}}} Simplify.
{{{(13D+2)/3 = 9}}}{{{1/3}}} Multiply both sides by 3.
{{{13D+2 = 28}}} Subtract 2 from both sides.
{{{13D = 26}}} Divide by 13.
{{{D = 2}}}
{{{R = 6D}}}
{{{R = 6(2)}}}
{{{R = 12}}}
{{{K = R+2}}}
{{{K = 12+2}}}
{{{K = 14}}}
Kirra is 14 years old, Reggie is 12 years old and Delia is 2 years old.