Hi iFruit,


The answers are correct! Thanks for the solutions.

Agree with atutor2001, you're really good.

Please help to solve the followings:


1) The product of n whole numbers 1 x 2 x 3 x 4 x 5 x …x (n - 1) x n has 28 consecutive zeros. Find the largest value of n.

2) Find the largest no. n such that there is only one whole no. k that satisfies
8/21 < n/(n+k) < 5/13

(Note: A < C < B means that value of C is between A and B, e.g. 4 < 9 < 16)

Thank you.

Thanks a lot.

Hi, just asking, how do I factorise the following sums:


a) a^3 + b^3

b) x^5 + x + 1

Thanks!

my answer for the lizard and snake question is:


the snake has a larger surface area in contact with the sand than the lizard. thus, there will be more heat transfer to the snake than the lizard.


the lizard moves only on two of its four legs. when it cannot stand the heat on the two legs on which it is traveling, it can always change to the other two legs. however, the snake has only one surface to travel on and cannot change to another surface when it cannot take the heat any longer.


can anyone confirm if my answer is right????

the ME:

kohjl:

The Question:
The farmer found that alot of caterpillars were eating his crops. The farmer sprayed alot of pesticides onto them. Which of the following is correct?

My answer:
Crops-increased
Fruits-increased

Reason: Even if the pesticides kill some of the plants, pesticides will kill most of the caterpillars. Since there are no more caterpillars feeding on the leaves, the number of crops will increase and therefore, the number of fruits will increase.

From: kohjl Jr

My answer was:

Crops-increased
Fruits-decreased

My reason: The pesticides killed most of the caterpillars. Since there are less caterpillars which feed on the plants, the plants increased. When the caterpillars which were the young of the butterfly decreased, the butterflies will also decrease. The butterflies are needed to help the flowers to pollinate. If there are less butterflies to help the plants pollinate, there will be less fruits as a flower can only become a fruit if it goes through pollination. Therefore, there will be lesser fruits.

:?: Am I correct or wrong? :stupid:

hey! you have the same answer as me!

kohjl:

justsay:

As you have mentioned it killed most of the caterpillars but not all. The remaining caterpillars will then multiply and feed of the fruits. So shouldnt it be crop increased and fruit decreased ?

I think catepillars eat leaves and not fruits. Worms eat fruits.
From: kohjl Jr

my answer was that the plant increased and the fruits decreased.

since the caterpillars feed on the plants, when the caterpillars' population decreases, the population of the plants will increase.

however, with less caterpillars, there will be less butterflies to pollinate the flowers of the fruit trees. wouldn't that result in the number of fruits born by the fruit trees decreasing?


that is my reasoning but i'm not sure though. hope someone can confirm it... hope i'm right....

justsay:

caroline3sg:

Any one can tell me your answer for the farmer spraying pesticides?

veg increase, fruit trees decreased ?

same answer... Hope it's correct...

Tang:

hot_chocolate:

my answer for the pot/kettle question was: there is less contact between the surface of kettle b(the one with air spaces) compared to kettle a( the one without air spaces) thus, heat travels more quickly to the kettle a than b, causing the water in it to boil faster.


is my answer correct? I didn't mention that air is a good conductor of heat. :frustrated: yikes!!!

Hi Hot_chocolate,

Your answer is quite the same as what is given here:

http://pslescience.blogspot.com/

Instead of 'heat travels more quickly', it states that 'Pot A gained more heat' - more contact.

Hi Tang, thanks! I feel much reassured...

my answer for the pot/kettle question was: there is less contact between the surface of kettle b(the one with air spaces) compared to kettle a( the one without air spaces) thus, heat travels more quickly to the kettle a than b, causing the water in it to boil faster.


is my answer correct? I didn't mention that air is a good conductor of heat. :frustrated: yikes!!!