Let’s call the third number “x”.

The first number is 20% more than the third number, which means it can be written as:

1.2x

Similarly, the second number is 50% more than the third number, which can be written as:

1.5x

To find what percent the first number is of the second number, we need to divide the first number by the second number and express the result as a percentage:

(1.2x ÷ 1.5x) × 100%

Simplifying the expression by cancelling out the “x” terms, we get:

(1.2 ÷ 1.5) × 100%

0.8 × 100% = 80%

Therefore, the first number is 80% of the second number.