Question

Mr. John started irrigating farmland at 15:35. At 16:21, 1/8 ofthe farmland was irrigated. At the same rate, what time did Mr.John finish irrigating the whole farmland? Give your answer in a24-hour clock format, such as 19:00.

Answer 1

From 15:35 hs to 16:00 hs there are 25 minutes

From 16:00 hs to 16:21 hs there are 21 minutes.

Then, From 15:35 hs to 16:21 hs there are 25 + 21 = 46 minutes.

It takes 46 minutes to irrigate 1/8 of the farmland. Then it takes 8 x 46 = 368 minutes to irrigate the whole farmland.

60 minutes are equivalent to 1 hour. To find how many hours are equivalent to 368 minutes we can use the next proportion:

`\frac{60\text{ minutes}}{368\text{ minutes}}=\frac{1\text{ hour}}{x\text{ hours}}`

Solving for x:

`\begin{gathered} 60x=1\cdot368 \\ x=(368)/(60) \\ x=6(2)/(15)\text{ hours} \end{gathered}`

6 hours are equivalent to 6x60 = 360 minutes. Then, 368 minutes are equivalent to 6 hours and 8 (= 368 - 360) minutes.

Mr. John started irrigating farmland at 15:35, after 6 hours, the time is 21:35 (15+6 = 21). Adding the other 8 minutes, we get: 35+8 = 43 minutes, and the time Mr. John finished irrigating the whole farmland is 21:43.