



 
Hi Maya, The problem is about two numbers, the first number and the second number. To write this question using mathematical notation I am going to replace the phrase "the first number" by the letter $x$ and the phrase "the second number" by the letter $y.$ To do this I would say
The first statement in the problem "Two numbers have a sum of 57." then become \[x + y = 57.\] The second statement is "Three times the first number is 13 less than the second number." Three times the first number is $3 \times x$ which is 13 less then $y.$ So you need to subtract 13 from $y$ to get to $3 \times x.$ hence \[3x = y  13.\] Solve this pair of equations for $x$ and $y.$ Make sure you verify your answer. Penny 



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