You are asked to find the team score, so it is convenient to let a variable represent that value. Let's call it "s", for "score". The problem statement tells you
.. Michaela scored s/5 . . . . . one fifth of the team's points
.. Aleah scored s/10 . . . . . . . one tenth o the team's points
These scores together are (s/5 +s/10) and that amount is 42 points.
.. s/5 +s/10 = 42
.. s(2/10 +1/10) = 42 . . . . . factor out s
.. s(3/10) = 42 . . . . . . . . . . form the sum of the numbers in parentheses
.. s = 42*10/3 = 140 . . . . . multiply by the inverse of the coefficient of s
The team scored 140 points.
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Michaela scored 140/5 = 28 points; Aleah scored 140/10 = 14 points.