Bonjour,
1)
a) 5 kb = 5 × 10³ bits
b) 3,2 Mb = 3,2 × 10⁶ bits
c) 150 Gb = 150 × 10⁹ bits = 1,5 × 10¹¹ bits
2)
a) 1 mn = 60 s
donc quantité d'informations recue en 1 mn = 28 × 10⁶ × 60 bits
= 1 680 × 10⁶ bits
= 1,68 × 10⁹ bits
b) 10⁹ ÷ 28 × 10⁶ = 1×10⁹ ÷ 28×10⁶
= 1/28 × 10⁹⁻⁶
= 1/28 × 10³
≈ 35,7 (s)
3)
a) 250 × 10⁶ × 60 = 15 000 × 10⁶ = 1,5 × 10¹⁰ bits
b) 10⁹ ÷ 250 × 10⁶ = 1×10⁹ ÷ 250×10⁶
= 1/250 × 10⁹⁻⁶
= 1/250 × 10³
= 0,004 × 10³
= 4 (s)
4)
a) 1 octet = 8 bit
donc : 28 × 10⁶ ÷ 8 = 28/8 × 10⁶ = 3,5 × 10⁶ (bits)
= 3,5 (Mb)
b) en 1 mn : 3,5 × 60 = 210 (Mo)
en 1 h : 3,5 × 3 600 = 12 600 (Mo)
c) 250 ÷ 3,5 ≈ 71,5 (s)
d) 250 Mo ÷ 120 s = 2,0833333333..... Mo/s
2,08333333..... × 8 = 16,6666666..... Mb/s
5)
a) 250 Mb/s = (250 ÷ 8) Mo/s = 31,25 Mo/s
b) 350 Mo ÷ 18 s = 19,4444444...... Mo/s
19,44444..... Mo/s = (19,4444..... × 8) Mb/s = 155,5555.... Mb/s
