randy and sandy are brother and sister. Randy is three less than twice Sandy's age. Together, their ages equal twent-four. How old is Sandy?

Sandy is 9 years old.

Step-by-step explanation:

R+S=24

R=2S-3

R=Randy, S=Sandy

Plug the value of R into the first equation.

2S-3+S=24

Now, simplify.

3S-3=24

Now, solve the equation for S. First add three to both sides.

3S=24+3=27

3S=27

Now divide both sides by 3.

S=9