Calculate the first part ($50\%$ of $60$)

Convert $50\%$ to a fraction or decimal and multiply by $60$: $\frac{50}{100} \times 60 = 0.5 \times 60 = 30$

$50\% \text{ of } 60 = 30$

Calculate the second part ($30\%$ of $40$)

Convert $30\%$ to a fraction or decimal and multiply by $40$: $\frac{30}{100} \times 40 = 0.3 \times 40 = 12$

$30\% \text{ of } 40 = 12$

Find the difference between the two values

Subtract the second value from the first value to find how much greater it is: $\text{Difference} = 30 - 12 = 18$

$30 - 12 = 18$