Simultaneous Concept

by Emily
(Singapore)

1600 participants took part in an event with mass dance and taiji activities. 30% of the 1300 mass dance participants were adults, while 40% of the taiji participants were children. Following a break, some participants from mass dance switched to taiji and some from taiji switched to mass dance. After the switch 25% of the mass dance participants were adults and 75% of the taiji participants were adults. How many mass dance participants were there after the break?

I think this is a case of a constant total but the variables are not constant and I cant seem to run away from simultaneous equations on this. I would appreciate your help on this! thanks!

Here's My Answer
by Zach
(Singapore)

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