Let's call the unknown number $x$. According to the problem, we have:

$3x - 7 = 20$

To solve for $x$, we’ll isolate it step-by-step.

1. Add 7 to both sides: $3x = 27$

2. Divide by 3: $x = 9$

So, the number is $x = 9$.

Would you like more details, or do you have any questions about this solution?

Here are some related questions for further practice:

1. A number multiplied by 5 and then increased by 3 gives 28. What is the number?
2. A number divided by 2, then added to 5, gives 15. What is the number?
3. Find a number that, when multiplied by 4 and then decreased by 9, gives 19.
4. A number is multiplied by 6 and then increased by 8 to result in 50. What is the number?
5. Twice a number, increased by 10, equals 34. What is the number?

Tip: When solving equations, aim to isolate the variable by reversing operations systematically.