Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
Class A is twice as big as Class B. Class A is also a third the size of Class C. If Class B has 20 people in it, how many people are in Class C?

### Response:
 ชั้นเรียน A มีขนาด 2*B = 2*20 = <<2*20=40>>40 คน
ชั้นเรียน C มีขนาด 3*A = 3*40 = <<3*40=120>>120 คน