A teacher has students. If she assigns 2 people per table, she needs 4 more tables. If she assigns 4 per table, she has 4 more tables left over. How many students are there?
Let T be the number of tables she has
So .....the total number of students = 2T + 2*4 = 2(T + 4)
And this equals 4(T - 4)
So
2(T + 4) = 4(T - 4) simplify
2T + 8 = 4T - 16 add 16 to both sides, subtract 2T from both sides
24 = 2T divide both sides by 2
12 = T
She has 12 tables....so she has 2(12 + 4) = 32 students