Given:
Let the time taken by Anu, Tanu, and Manu be \(5x, 8x,\) and \(10x\) hours, respectively.
The total work is considered as the Least Common Multiple (LCM) of their individual times: \(\text{LCM}(5x, 8x, 10x) = 40x\) units.
When working together, their combined rate is \(8 + 5 + 4 = 17\) units/hour.
They worked for \(8 \text{ hours/day} \times 4 \text{ days} = 32\) hours.
The total work completed is \(17 \text{ units/hour} \times 32 \text{ hours} = 544\) units.
Since the total work is \(40x\), we have: \(40x = 544\), which gives \(x = \frac{544}{40} = \frac{68}{5} = 13.6\).
They worked for 6 days, at a rate of 6 hours and 40 minutes per day.
Convert 6 hours 40 minutes to hours: \(6 + \frac{40}{60} = 6 + \frac{2}{3} = \frac{20}{3}\) hours/day.
Total hours worked by Anu and Tanu: \(6 \text{ days} \times \frac{20}{3} \text{ hours/day} = 40\) hours.
Their combined rate is \(8 + 5 = 13\) units/hour.
Work done by Anu and Tanu: \(13 \text{ units/hour} \times 40 \text{ hours} = 520\) units.
Total work = 544 units.
Remaining work = \(544 \text{ units} - 520 \text{ units} = 24\) units.
Manu's work rate is 4 units/hour.
Time required for Manu to complete the remaining work = \(\frac{24 \text{ units}}{4 \text{ units/hour}} = 6\) hours.
A box contains 16 red, 12 white, and 15 yellow identical marbles. A man picks one marble at a time without replacement. How many times must he pick a marble to be 100% certain of picking at least 3 white marbles?