Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
MATHS question, plz somebody help me. I'm really stuck. Thanks a million...?
The six friends leave the hotel to catch the last train home, which leaves in 40 minutes.
However before reaching the station, they must cross a deep river. To do this they must use a rowing boast that holds only three people, but has a paddle as well as two oars! It takes one person 11 minutes to row across the river in either direction, two people 6 minutes and three people 4 minutes.
From the far bank, it will take 6 minutes to get to the station. None of the friends can swim, and they cannot leave anyone behind. Can they make it to the train, and if so, how?
9 Answers
- Anonymous1 decade agoFavorite Answer
Okay, there are two sides of the bank, the boat needs to go back to collect the others. So side A is your starting bank, side B is your finishing bank.
Send three people over = 4 minutes
Side A= 3 people Side B = 3 People
Send two back = 6 minutes
Side A = 5 People Side B = 1 person
Send three over = 4 minutes
Side A = 2 people Side B = 4
Send two people back = 6 minutes
Side A = 4 people Side B = 2
Send three people over = 4 minutes
Side A = 1 person Side B =5 people
Send two back = 6 minutes
Side A = 3 people Side B =3 people
Send the final 3 over = 4 minutes
Side A = 0 Side B = 6
Now add up the minutes = 34 minutes
Plus the 6 minutes to run = 40 minutes
They'll make the train on time!
EDIT: Why so many thumbs down?! It's simple math, I've set similar problems to my class.
Source(s): I'm a teacher :) - Jun AgrudaLv 71 decade ago
1st going 4 min: drops 1 friend, 1 now is on the other side
1st return 6 min: fetches 1 more
2nd going 4 min: drops 1 friend, 2 now are on the other side
2nd return 6 min: fetches 1 more
3rd going 4 min: drops 1 friend, 3 now are on the other side
3rd return 6 min: fetches 1 more
last going 4 min: all the 3 disembarks, 6 now are on the other side
Going back and forth they spend (in minutes):
= 4 + 6 + 4 + 6 + 4 + 6 + 4
= 34
Answer: Yes. They can make it. The other 6 minutes they will spend getting to the station.
- ?Lv 45 years ago
whats up, the solutions are 15 and 20. x^2+y^2=625 a million/3x=a million/4y so x=3/4y Now we replace the x=3/4y expression interior the x^2+y^2=625 expression. You try this via changing x with 3/4y, and then for this reason squaring it basically via fact the expression shows. as quickly as you are trying this you're left with 625= 9/16y^2 + y^2. You upload the expression and you're left with 625=25/16y^2. then you definitely divide the two factors via 25/sixteen or multiply the two factors via sixteen/25, although you prefer to look at it. and you're left with 4 hundred=y^2. you're taking the sq. process the two factors y^2 and 400, and which will supply you y=20. then you definitely plug that fee into the 1st actual expression we observed of 625=x^2+y^2, different than now y=20. so your new fee is 625= x^2 +20^2. this suggests 625=x^2+4 hundred. Subtract 4 hundred from 625, and you get 225. so... 225=x^2, so x=15. you are able to extra verify this via on account that the adaptation between 20 and 15 is 5. Which fairly genuine is a million/3 of 15 and a million/4 of 20. wish this helps, be at liberty to e mail me with anymore questions. sturdy success with college.
- Anonymous1 decade ago
They can make it back just in time to get the train!
The way to do it is as follows:
Three people go to the far bank. 4 minutes
Two people return. 6 minutes
Three more to the other side. 4 minutes
Two back. 6 minutes.
Three there. 4 minutes.
Two back . 6 minutes.
Three there. 4 minutes.
This takes us up to 34 minutes. Then everyone hops out and does a runner for the station in the final 6 minutes.
Lets hope they remembered to buy their tickets beforehand...
- How do you think about the answers? You can sign in to vote the answer.
- YaybobLv 71 decade ago
1-2-3 row over (4 mins) and 1-2 row back (6 mins), leave 3
1-2-4 row over (4 mins) and 1 rows back (11 min), leave 2-4
1-5-6 row over (4 mins) with 11 mins to spare (29 mins total)
Apparently there are two solutions, one taking 34 minutes and giving them just enough time, the other a little quicker. What's with the thumbs down? Did I overlook something?
- 1 decade ago
6 people leave the hotel
it takes 11 minutes for 1 person to cross th river
it takes 6 minutes for 2 people
it takes 4 minutes for 3 people.
So, 3 people get on the boat and cross the river(4 minutes).
then 1 person rows back (11 minutes).
then he takes 2 people on the boat and goes to the other side(4 minutes).
goes back(11 minutes).
gets the last person(6 minutes)
So if you add the time, it takes them 36 minutes to cross the river. if they run relly fast frm the hotel to the river and the river to the train station, they should be able to make it. lol.
- Anonymous1 decade ago
They can make it like this.
3 cross = 4 min
2 stay 1 returns =11 min
3 cross = 4 min
1 more stays 2 return = 6 min
3 cross = 4 min
6 run to station = 6 min
Total = 35 minutes with 5 minutes to spare
- 1 decade ago
so 3 of them would go first across which would take 4 minutes.
one would get down and the two will get the one from the other side it would take 6 min. and the process will repeat for 3 times so it would take 30 min. and they will run to the train station for 6 min. that would result 36 min. travel and they would make it to the train
- The WolfLv 61 decade ago
I'll label the people a,b,c,d,e,f
a,b & c row over, drop off a........4min
b&c row back and pick up d......6min
b,c & d row over, drop off b&c...4min
d rows back and picks up e&f...11min
d,e & f row over........................4min
a,b,c,d,e,f go to station............6min
total = 35min
.,.,.