ITPEC FE Morning October 2020 Question 30

Source exam: ITPEC FE Morning October 2020Topic: Networks

ITPEC FE Morning October 2020 — Question 30 of 80

Data transmission time — calculate transfer duration considering line efficiency.

Given: file = 10⁶ bytes, line = 64 kbit/s, efficiency = 80%

Step-by-step:
- Convert file size to bits: 10⁶ × 8 = 8 × 10⁶ bits

- Effective throughput: 64 × 10³ × 0.8 = 51,200 bit/s

- Time = 8,000,000 / 51,200156 seconds

Formula: time = file_size_in_bits / (line_speed × efficiency)

Why not others:
- (a) 19.6 — forgot to convert bytes to bits

- (b) 100 — arithmetic error or wrong unit handling

- (c) 125 — ignored 80% efficiency (8,000,000 / 64,000 = 125)

Key rule: Always convert bytes → bits first, then apply efficiency to the line speed.

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