A convex lens of focal length `30 cm` and a concave lens of focal length `60 cm` are placed in combination. If an object is placed `40 cm` away from the combination, find the position of the image.

Explanation

To solve the problem step by step, we will follow these steps:

### Step 1: Identify the Focal Lengths
- The focal length of the convex lens (f1) is +30 cm (positive because it is a convex lens).
- The focal length of the concave lens (f2) is -60 cm (negative because it is a concave lens).

### Step 2: Calculate the Focal Length of the Combination
The formula for the focal length (F) of two lenses in combination is given by:
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