1. Denis housed chameleons that can change color only to two colors: red and brown. Initially, the number of red chameleons was five times the number of brown chameleons. After two brown chameleons turned red, the number of red chameleons became eight times the number of brown chameleons. Find out how many chameleons Denis has.
Solution. Let $t$ be the number of brown chameleons Denis had. Then the number of red chameleons was $5t$. From the problem statement, we get the equation $5 t+2=8(t-2)$. Solving this, we find $t=6$. Therefore, the total number of chameleons is $6 t$, which is 36.

Answer. 36

Recommendations for checking. Only the correct answer - 0 points. Answer with verification - 1 point. Correctly formulated equation, but incorrectly solved not due to arithmetic - no more than 4 points. No justification for the formulation of the equation, but it is clear from the context what the author meant - do not deduct.