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

### Instruction:
Out of the 80 students who took the biology exam, only 2/5 of them managed to score 100%. If a score below 80% qualified as failing, and 50 percent of the remaining students who didn't score 100% managed to score over 80%, calculate the number of students who failed the exam.

### Response:
 Ikiwa wanafunzi 2/5 waliofanya mtihani wa biolojia walipata alama 100%, basi wanafunzi 3/5 hawakupata alama 100%. Idadi ya wanafunzi ambao hawakupata alama 100% ni 3/5*80 = <<3/5*80=48>>48
Kati ya wanafunzi 48 ambao hawakupata alama 100%, 50/100*48 = <<50/100*48=24>>24 wanafunzi walipata alama chini ya 80%.