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  1. #1
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    Please Help Me,

    Whats the easiest and most simplest way to understand and work out this solution. Please show any shortcuts. Thanks

    A.Ben sails 1/3 of his trip at 4km/h, the next 1/3 at 8 km/h and the last 1/3 at 6 km/h. The trip takes him 9 hours and 45 minutes. How far was the complete trip ?

    B.In a zoo there are 17 more monkeys than lions and 30 more lizards than lions. If there were 151 animals in total, how many of each animal are there ?

    Thanks
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by chhoeuk View Post
    Please Help Me,

    Whats the easiest and most simplest way to understand and work out this solution. Please show any shortcuts. Thanks

    A.Ben sails 1/3 of his trip at 4km/h, the next 1/3 at 8 km/h and the last 1/3 at 6 km/h. The trip takes him 9 hours and 45 minutes. How far was the complete trip ?
    Note: 9 hours 45 mins is 39/4 hours.


    Recall that \mbox { Speed } = \frac { \mbox { Distance }}{ \mbox { Time }}

    \Rightarrow \mbox { Time } = \frac { \mbox { Distance }}{ \mbox { Speed }}

    Let D be the total distance traveled
    Let t_1 be the time for the first part of the journey
    Let t_2 be the time for the second part of the journey
    Let t_3 be the time for the last part of the journey


    For the first third of the trip we travel \frac {1}{3} D:

    t_1 = \frac {distance}{time} = \frac { \frac {D}{3}}{4} = \frac {D}{12}

    For the second part of the journey, we also travel \frac {1}{3} D:

    t_2 = \frac {distance}{speed} = \frac { \frac {D}{3}}{8} = \frac {D}{24}

    For the last part of the trip, we also travel \frac {1}{3} D:

    t_3 = \frac {distance}{speed} = \frac { \frac {D}{3}}{6} = \frac {D}{18}

    Now all these times must add up to \frac {39}{4} hours.

    So we have:

    t_1 + t_2 + t_3 = \frac {39}{4}

    \Rightarrow \frac {D}{12} + \frac {D}{24} + \frac {D}{18} = \frac {39}{4}

    solving for D we get: \boxed { D = 54 \mbox { km } }
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  3. #3
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by chhoeuk View Post

    B.In a zoo there are 17 more monkeys than lions and 30 more lizards than lions. If there were 151 animals in total, how many of each animal are there ?
    i think there's something wrong with this question...but maybe i'm too sleepy. i'm going to bed. good luck
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  4. #4
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    Jhevon says it's wrong because after solving for it, he probably gets a number and two thirds lions, which clearly cannot be in this time and in this world... unless we define a third of a lion as a cat, a third of a monkey as Taco Bell's chihuahua, and a third of a lizard as its head. Also, why does the zoo only have three types of animals? In any case, my house is much more of a zoo than that. We have: cats, dogs, lizards, cockroaches, different colored ants, birds, a smurf, and an orange snork to name a few... but no lions or monkeys. Maybe I should open a zoo.

    What I mean is please check for typos either in the numbers or in the animals.
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  5. #5
    Newbie servantes135's Avatar
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    Quote Originally Posted by chhoeuk View Post
    Please Help Me,

    B.In a zoo there are 17 more monkeys than lions and 30 more lizards than lions. If there were 151 animals in total, how many of each animal are there ?

    Thanks

    L= lions
    M= monkey
    and Z= Lizards

    M=L+17
    Z=L+30

    M+L+Z = 151

    (L+17)+L+(L+30) = 151
    M Z

    3L+47= 151

    3L = 104
    L = 34.6666666666666666 and it's kind hard to have only part of an animal.
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