First, let me post the rules for a qualifying child.
Qualifying Child
Relationship — the taxpayer’s child or stepchild (whether by blood or adoption), foster child, sibling or step-sibling, or a descendant of one of these.
Residence — has the same principal residence as the taxpayer for more than half the tax year. Exceptions apply, in certain cases, for children of divorced or separated parents, kidnapped children, temporary absences, and for children who were born or died during the year.
Age — must be under the age of 19 at the end of the tax year, or under the age of 24 if a full-time student for at least five months of the year, or be permanently and totally disabled at any time during the year.
Support — did not provide more than one-half of his/her own support for the year.
They both meet the age and residence requirements. They twin who earned $5,300 is your dependent.
The twin who earned $22,000, maybe not.
When you look at support, you have to look at every dollar spent in support. From the obvious; food, shelter, clothing, medical etc. to the less obvious.
Money spent on recreation, from going out clubbing, to the movies, buying bubble gum, everything counts. She can't have provided more than half. The amount we are looking at is $22,000. If she spent that entire amount on herself (didn't put it in savings or an investment), then you would have to at least contributed an slightly more than equal amount on her behalf. My guess would be no.
