Answer: 35
Explanation:
Let's assume that Mr. Nelson took "x" students on the trip.
According to the problem, the observatory charges a trip fee of $100, which Mr. Nelson had to pay regardless of how many students he took.
In addition to that, he also had to pay $6.50 per student. So the total cost of the trip can be expressed as:
Total cost = $100 + ($6.50 * number of students)
We know from the problem that the total cost of the trip was $327.50. So we can set up an equation:
$327.50 = $100 + ($6.50 * x)
Now we can solve for "x" by first subtracting $100 from both sides:
$327.50 - $100 = $6.50x
$227.50 = $6.50x
Finally, we can solve for "x" by dividing both sides by $6.50:
x = $227.50 ÷ $6.50
x ≈ 35
Therefore, Mr. Nelson took approximately 35 students on the field trip.