`2//3` of the aliens on Planet X are Zorgs, whose average IQ is 120. The rest are Weebs, whose average IQ is 180. What is the average IQ of all the aliens on Planet X ?

Answer

To find the average IQ of all the aliens on Planet X, we can follow these steps:

### Step 1: Determine the proportions of Zorgs and Weebs
We know that \( \frac{2}{3} \) of the aliens are Zorgs and the remaining \( \frac{1}{3} \) are Weebs.

### Step 2: Identify the average IQs
- The average IQ of Zorgs is 120.
- The average IQ of Weebs is 180.

### Step 3: Calculate the total IQ contribution from Zorgs
To find the total IQ contribution from Zorgs, we can multiply their proportion by their average IQ:
\[ \text{Total IQ from Zorgs} = \left(\frac{2}{3}\right) \times 120 = 80 \]

### Step 4: Calculate the total IQ contribution from Weebs
Similarly, we can calculate the total IQ contribution from Weebs:
\[ \text{Total IQ from Weebs} = \left(\frac{1}{3}\right) \times 180 = 60 \]

### Step 5: Add the total IQ contributions
Now, we add the total IQ contributions from both Zorgs and Weebs:
\[ \text{Total IQ} = 80 + 60 = 140 \]

### Step 6: Calculate the average IQ of all aliens
Since we are considering the average IQ of all aliens, we need to divide the total IQ by the total proportion:
\[ \text{Average IQ} = \text{Total IQ} = 140 \]

Thus, the average IQ of all the aliens on Planet X is **140**.

---