Some really , really hard maths homework... "SIGH"! (1 Viewer)

[sarah13081234]

yeah, just as you'd expect.. peeps, my teacher (even though he's soooo hot), has always been known to give us some really hard maths h/w. Im not in yr 12 doing MXE2 btw, i'm in yr 10, doin da school cert this year and he gave us these questions to warm us up. They're due quite soon, and i hav no idea to do em, any help guys?

Q. 1 The distance from the centre of a clock to the tip of its second hand is 6 cm. How far, to the nearest metre, will the tip of the second hand travel in one day????
(pic attached =)_) (Note: This diagram is almost exactly the same as the one he showed us, if that actually matters for the question's answer, I wouldnt know..) http://community.boredofstudies.org/attachment.php?attachmentid=16763&stc=1&d=1216897063

Q. 2 (rEALLY TRICKY!) Henry has programmed his computer so that his whole screen light sup periodically in combinations of three primary colours. The screen lights up for one second each time. When all colours are programmed to appear at the same time the screen colour is white. When no colours are programmed to appear the screen is black.
Henry programs the primary colours as shown.
BLUE: Every 7 seconds
GREEN: Every 11 seconds
RED: Every 17 seconds
He starts the green program 3 seconds after the starts the blue program. He starts the red program 12 seconds after he starts the green program. How many seconds after Henry starts the blue program will the screen appear white?

Q 3. (Im stuck on dis badly) Sophia has two bags. In each bag there are 4 white chess pawns and 4 black chess pawns. Without looking, Sophia takes a pawn from each bag. What is the probability that at least one of the pawns will be black?

Q 4. (Definitely the last and hardest of em all!!!) The diagram shows a square with one corner, Q at (-34, 34) and another corner, P, at (-26,0). http://community.boredofstudies.org/attachment.php?attachmentid=16764&stc=1&d=1216897716



Im in distress lol, if you can help, i'll love you 4 everrrrrrr!!! anyq uestion is fine!!!

 

[lolokay]

yeah, just as you'd expect.. peeps, my teacher (even though he's soooo hot), has always been known to give us some really hard maths h/w. Im not in yr 12 doing MXE2 btw, i'm in yr 10, doin da school cert this year and he gave us these questions to warm us up. They're due quite soon, and i hav no idea to do em, any help guys?

Q. 1 The distance from the centre of a clock to the tip of its second hand is 6 cm. How far, to the nearest metre, will the tip of the second hand travel in one day????
(pic attached =)_) (Note: This diagram is almost exactly the same as the one he showed us, if that actually matters for the question's answer, I wouldnt know..) http://community.boredofstudies.org/attachment.php?attachmentid=16763&stc=1&d=1216897063

6*2pi*60*24 = 54286cm

Q. 2 (rEALLY TRICKY!) Henry has programmed his computer so that his whole screen light sup periodically in combinations of three primary colours. The screen lights up for one second each time. When all colours are programmed to appear at the same time the screen colour is white. When no colours are programmed to appear the screen is black.
Henry programs the primary colours as shown.
BLUE: Every 7 seconds
GREEN: Every 11 seconds
RED: Every 17 seconds
He starts the green program 3 seconds after the starts the blue program. He starts the red program 12 seconds after he starts the green program. How many seconds after Henry starts the blue program will the screen appear white?

they will be white after a number of seconds n such that
n = 7a = 11b + 3 = 17c + 15
where a, b and c (and all other pronumerals) are positive integers
11b + 3, 17c + 15 and therefore 4b + 3, 3c + 1 must both be divisible by 7
this occurs when b = 1 + 7k, c = 2 + 7p
substitute into the equations for n,
n = 7a = 14 + 11*7k = 49 + 17*7p
11k = 17p + 5
occurs when p=1, k=2

so the number of seconds is 49 + 17*7 = 168

Q 3. (Im stuck on dis badly) Sophia has two bags. In each bag there are 4 white chess pawns and 4 black chess pawns. Without looking, Sophia takes a pawn from each bag. What is the probability that at least one of the pawns will be black?

P(2 white) = 1/2*1/2=1/4
P(not 2 white = at least one black) = 3/4

Q 4. (Definitely the last and hardest of em all!!!) The diagram shows a square with one corner, Q at (-34, 34) and another corner, P, at (-26,0). http://community.boredofstudies.org/attachment.php?attachmentid=16764&stc=1&d=1216897716



Im in distress lol, if you can help, i'll love you 4 everrrrrrr!!! anyq uestion is fine!!!

what's the question?

 

[Pwnage101]

the Q's arent that hard that they deserve to be placed on an MX2 forum, couple of weeks out of most ppl's trials!!!

 

[lolokay]

yeah, shouldn't be in this forum

 

[sarah13081234]

yeah, shouldn't be in this forum

umm soz, but the last question is supposed to be:

A rotation of 180 degrees around a point, F, takes the point, Q, to a new point (34,176). What is the distance between point F and point R?

 

[sarah13081234]

thanks for ur help so far lolokay, i'll know not to post it in this forum in the future, my bad

 

[lolokay]

umm soz, but the last question is supposed to be:

A rotation of 180 degrees around a point, F, takes the point, Q, to a new point (34,176). What is the distance between point F and point R?

Q is (-34, 34)
F is the midpoint, so it is (0, 105)
R is the corner of the square next to Q right?
R is (0, 42)
so FR is 63

 

[sarah13081234]

Q is (-34, 34)
F is the midpoint, so it is (0, 105)
R is the corner of the square next to Q right?
R is (0, 42)
so FR is 63

shit, ur right!!!
thanks so much, lolokay!!!

 

[sarah13081234]

umm lolokay, in the 1st question, how did you get from 4b + 3 to b = 1 + 7k and from 3c + 1 to 2 + 7p? and for 2nd, tell me how u got to that equation,
soz for l8 post, thanks!

 

[lyounamu]

umm lolokay, in the 1st question, how did you get from 4b + 3 to b = 1 + 7k and from 3c + 1 to 2 + 7p? and for 2nd, tell me how u got to that equation,
soz for l8 post, thanks!

11b+3 must be divisible by 7 so you get the separate entity for b that would enable it to be divisible by 7. so b = 7k +1 to make 11b+3 to 77k+14 which is divisible by 7.

Same thing for 17c +15. c = 7t + 2 becomes 119t + 49 which is also divisible by 7.

7a = 77k + 14 = 119t + 49
Try
7a = 119t + 49
a = 17t + 7
t =1 and a = 24 because you wish to find the lowest pair.

Then,
substitute either t=1 or a =24 to find the answer. Either one should work.

119 . 1 +49 = 168

OR 7a = 7 . 24 = 168

4) Are you referring to q4 for equation ?

M is the mid-point. So use the mid-poing formula.
F(x,y) = F(-34+34/2, 34+176/2)
= F(0, 105)

Then use the distance formula to find FR.

 

[sarah13081234]

11b+3 must be divisible by 7 so you get the separate entity for b that would enable it to be divisible by 7. so b = 7k +1 to make 11b+3 to 77k+14 which is divisible by 7.

Same thing for 17c +15. c = 7t + 2 becomes 119t + 49 which is also divisible by 7.

7a = 77k + 14 = 119t + 49
Try
7a = 119t + 49
a = 17t + 7
t =1 and a = 24 because you wish to find the lowest pair.

Then,
substitute either t=1 or a =24 to find the answer. Either one should work.

119 . 1 +49 = 168

OR 7a = 7 . 24 = 168

4) Are you referring to q4 for equation ?

M is the mid-point. So use the mid-poing formula.
F(x,y) = F(-34+34/2, 34+176/2)
= F(0, 105)

Then use the distance formula to find FR.

hey lyounamu, thanks for explaining both, i was just wondering.. i've just seemed to notice that many of the questions i have got questions that are like q.4 which deal with a certain point that rotates around a certain degree around another certain point to get to another. Again, could you please explain why F, in q.4 would be the mid-point of the line? Why is it exactly middle of the line I just dont understand....



thanks so much, sarah

 

[lolokay]

The distance from a point (Q) to a point that it is rotated from (F) will remain constant. A 180* turn makes a straight line..