Adam solved 12 math problems and 42 minutes if he continues at this pace, how many minutes will it take him to solve 20 math problems?

1. Given ratio: \frac{12 \text{ problems}}{42 \text{ minutes}}
2. Let \( x \) be the number of minutes to solve 20 problems: \frac{20 \text{ problems}}{x \text{ minutes}}
3. Equate the ratios: \frac{12}{42} = \frac{20}{x}
4. Cross-multiply: 12x = 42 \times 20
5. Solve for \( x \): 12x = 840
6. x = \frac{840}{12}
7. x = 70

Therefore, it will take \( x = 70 \text{ minutes} \).