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A standard multiple-tube fermentation test was conducted on a sample of water from a surface stream. The results of the analysis for the confirmed test are given below.
MPN Index and 95% confidence limits for combination of positive results when five tubes used per dilutions (10 ml, 1.0 ml 0.1 ml)
Using the above MPN Index table, the most probable number (MPN) of the sample is
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- 20
- 33
- 260
- 330
Correct Option: C
| Q = | R2/3s01/2A | |
| n |
n = 0.015
q = 1728 m³/day.
| A = | × D² = | × (0.3)² = 0.07 m² | ||
| 4 | 4 |
| R = | = | = | = | = 0.075 m | ||||
| P | πD | 4 | 4 |
| Q = | R2/3s1/2 × A | |
| n |
| = | = | × (0.075)2/3 × |  |  | 1/2 | × 0.07 | |||
| P | 0.015 | 280 |
= 0.0495 = 0.05 m³/s = 4320 m³/day
| = | = 0.4 | |||
| Q | 4320 |
From the graph,
| = 0.5 ⇒ 0.5, × 0.3 = .15 m = 150 mm | ||
| D |
| For | = 0.5, | = 0.8 | ||
| D | V |
| ∴ v = 0.8 × V = 0.8 × | = 0.8 × | = 0.8 × 714 = 0.57 m/s | ||
| A | 0.07 |
