Answer:
Let's assume that the seller bought x big eggs and y small eggs. Since he bought a total of 1,000 eggs, we know that x + y = 1000.
The total cost of the eggs is 2,750 baht, so we can write an equation based on the cost per egg:
3.50x + 1.50y = 2,750
We also know that the seller made a profit of more than 300 baht, so we can write another equation based on the revenue and cost:
3.50x + 1.50y - 2,750 > 300
Simplifying this inequality, we get:
3.50x + 1.50y > 3,050
We can solve this system of equations by multiplying the second equation by 2 and subtracting it from the first equation:
3.50x + 1.50y - 7x - 3y = -1,450
-3.50x - 3y = -1,450
x + y = 1,000
Simplifying this, we get:
-3.50x - 3y = -1,450
x + y = 1,000
Multiplying the second equation by 3.5 and adding it to the first equation, we get:
-1.5y = -100
y = 66.67
Since y must be a whole number, we can round up to 67. Therefore, the seller bought 933 big eggs (x = 933) and 67 small eggs (y = 67).
To check which size of eggs were sold more, we can calculate the total revenue from selling the eggs:
Revenue = (3.50 baht/egg) * 933 big eggs + (1.50 baht/egg) * 67 small eggs
Revenue = 3,455.50 baht
Since the total revenue is greater than the total cost of 2,750 baht, we know that the seller made a profit. Moreover, the profit must be more than 300 baht, as stated in the problem. Therefore, the seller must have sold more big eggs than small eggs, since the profit margin is greater for the big eggs.
Explanation: