A farmer grows some tomato plants. Three of the plants die, and each of the rest plants grow 12 tomatoes. if the farmer picks 48 tomatoes, how many plants did he start with?

Let x be the number of plants the farmer started with.

The number of plants that remain is x - 3.
The total number of tomatoes that grow is (x - 3) × 12.
Since the farmer picks 48 tomatoes, (x - 3) × 12 = 48.
Thus, x - 3 = 48 / 12 = 4.
Therefore, the farmer started with x = 4 + 3 = <<4+3=7>>7 plants. Answer: \boxed{7}.

Let's break down the problem step-by-step to find the solution:

Step 1: Let's assume that the farmer started with "x" tomato plants.

Step 2: Three of the plants died. This means the farmer has "x - 3" tomato plants remaining.

Step 3: Each of the remaining plants grows 12 tomatoes. So, the total number of tomatoes from the remaining plants is "(x - 3) * 12".

Step 4: The farmer picked 48 tomatoes. This means that "(x - 3) * 12 = 48".

Step 5: Now, we can solve the equation to find the value of "x".

(x - 3) * 12 = 48

Dividing both sides of the equation by 12:

(x - 3) = 4

Adding 3 to both sides of the equation:

x = 7

Therefore, the farmer started with 7 tomato plants.

To find out how many tomato plants the farmer started with, we can use algebra.

Let's assume the number of tomato plants the farmer started with as 'x.'

According to the given information, three plants died, so the remaining plants are 'x - 3'.

Each of the remaining plants grows 12 tomatoes, so the total number of tomatoes is '(x - 3) * 12.'

Since the farmer picked 48 tomatoes, we can set up the equation:

'(x - 3) * 12 = 48'

Now, let's solve this equation to find the value of 'x.'

Divide both sides of the equation by 12:

(x - 3) = 48 / 12

Simplify:

x - 3 = 4

Add 3 to both sides of the equation:

x = 7

Therefore, the farmer started with 7 tomato plants.