Question 398950: tina is twice as old as her cousin sally. the sum of their ages is 21 years. How old is each girls? Explain. Answer by teishad(7) (Show Source):
You can put this solution on YOUR website! Tina is going to be represented by T
Sally is going to be represented by S
T=2S
because tina is twice as old as sally
T+s=21
because the sum of their ages is 21
plug in the first equation to the second.
2s+s=21
3s=21
divide by 3
s=7
then plug in s=7 to the first equation
2s=t
2*7=14
sally is 7 and tina is 14,
