When you see 'is' that means an = sign
When you see 'of' that means a x (multiplication) sign
So
30 is 60% of what number
Let us define this 'what number' as x.
So:
30 is 60% of x
Translating that into an equation based on what I said above, we get:
\(\sf{30 = \frac{60}{100}\times x}\)
Solve for x:
\(\sf{\frac{30\times100}{60}=x\)
And simplfying that:
\(\sf{x=50}\)
So your final answer is \(\sf{\boxed{50}}\)