Multiple choice question: There are 20 monks in the temple. I made 20 steamed buns in one night, 1 adult monk ate 3 steamed buns, and 3 young monks ate 1 steamed buns, and just finished eating them. There are adult monks and young monks in the temple.

a 0.20 B 4. 14 C 8. 15D 5. 15

Considering that the primary school questions are relatively simple, the test is only the skills of doing multiple-choice questions. If you have the ability, you can work out the problem in some way.