Maths, Addmaths and Statistics: Post your doubts here!

[ashiqbal]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_w07_qp_1.pdf
q no 17 part b
i never do understand such questions plz explain how to solve them lyk they say wat wud b the value of n to make it aperfect square and bla bla plz explain this question to me~..

do you understand the first part? then i will only explain the second part.
this question asks you about LCM of 540 and 225. in LCM you take the common factors once and then all the other extra factors as they are:
3*3*5*5
2*2*3*3*3*5
you make on group of two three's another group of two three's and the last group of two fives. the remaining, you write them down as one.
so now it becomes 2*2*(3*3)*(3*3)*3*(5*5)*5 = 2*2*3*3*3*5*5 (take those in groups as one number only.)= 2700
this means that 2700 is divisible by both 540 and 225. divide 2700 by 225 to get n = 12

 

[HarisLatif]

6.5*8=52mm=5.2cm(at least width needed)..
but the answer should be in centimetres,soit will be 6 cm at least...hope u understand...

i did the same but why can't the width be 5.2 cm?

 

[kitecrystal]

i did the same but why can't the width be 5.2 cm?

because the question says it should be given in centimetres,read that again...

 

[syed1995]

do you understand the first part? then i will only explain the second part.
this question asks you about LCM of 540 and 225. in LCM you take the common factors once and then all the other extra factors as they are:
3*3*5*5
2*2*3*3*3*5
you make on group of two three's another group of two three's and the last group of two fives. the remaining, you write them down as one.
so now it becomes 2*2*(3*3)*(3*3)*3*(5*5)*5 = 2*2*3*3*3*5*5 (take those in groups as one number only.)= 2700
this means that 2700 is divisible by both 540 and 225. divide 2700 by 225 to get n = 12

ash mjh say probability hi nai solve horahi ab!! saala jahan probablity aarahi hai mein permutation combination use kar raha houn lol

 

[HarisLatif]

because the question says it should be given in centimetres,read that again...

5.2 is already in centimetres

 

[kitecrystal]

ash mjh say probability hi nai solve horahi ab!! saala jahan probablity aarahi hai mein permutation combination use kar raha houn lol

add math after effects...lol

 

[syed1995]

add math after effects...lol

hahaha yeah .. LOL

 

[Haris Bin Zahid]

ash mjh say probability hi nai solve horahi ab!! saala jahan probablity aarahi hai mein permutation combination use kar raha houn lol

Solve Q7 in this.....if u r really proficient in probability. Yeh kr liya tau samjho you are probability champion
http://www.xtremepapers.com/papers/... O Level/Statistics (4040)/4040_w11_qp_22.pdf

 

[kitecrystal]

5.2 is already in centimetres

the statement mean that we should give answer of width in EXACT centimetres and nothing more or less than a whole cm....
now,as the pencils occupy 5.2cm,width must be given exact 6 cm ..ok?

 

[fatikhalid]

do you understand the first part? then i will only explain the second part.
this question asks you about LCM of 540 and 225. in LCM you take the common factors once and then all the other extra factors as they are:
3*3*5*5
2*2*3*3*3*5
you make on group of two three's another group of two three's and the last group of two fives. the remaining, you write them down as one.
so now it becomes 2*2*(3*3)*(3*3)*3*(5*5)*5 = 2*2*3*3*3*5*5 (take those in groups as one number only.)= 2700
this means that 2700 is divisible by both 540 and 225. divide 2700 by 225 to get n = 12

thankuuu!! well how to do those questions in wich they ask wat shud b multiplied with a particualar no to make it a perfect square?

 

[syed1995]

Solve Q7 in this.....if u r really proficient in probability. Yeh kr liya tau samjho you are probability champion
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Statistics (4040)/4040_w11_qp_22.pdf

lols stats kardunga .. zaroor kardunga .. paper hojanay doo =P

 

[HarisLatif]

the statement mean that we should give answer of width in EXACT centimetres and nothing more or less than a whole cm....
now,as the pencils occupy 5.2cm,width must be given exact 6 cm ..ok?

okay!

 

[ashiqbal]

see s_10_qp22 q11 and please explain why in the marking schemes are widths given 2,2,5,5,10 instead of 1,1,2.5,2.5,5 because they have asked for 1 cm = 2 seconds in the question. so have they actually given the range in the ms or the width of each bar?
http://www.xtremepapers.com/papers/...Calculator Version) (4024)/4024_s10_qp_22.pdf
http://www.xtremepapers.com/papers/...Calculator Version) (4024)/4024_s10_ms_22.pdf

 

[kitecrystal]

see s_10_qp22 q11 and please explain why in the marking schemes are widths given 2,2,5,5,10 instead of 1,1,2.5,2.5,5 because they have asked for 1 cm = 2 seconds in the question. so have they actually given the range in the ms or the width of each bar?
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_s10_qp_22.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_s10_ms_22.pdf

which question?

 

[ashiqbal]

6.5*8=52mm=5.2cm(at least width needed)..
but the answer should be in centimetres,soit will be 6 cm at least...hope u understand...

okay!

i believe this is the wrong explanation.
they have asked for what? the smallest width that can ALWAYS hold 8 pencils, right? so we have to take the upper bound of the pencils's diameter. this is because if we take the lower bound of the pencils,6.5mm, the box could not hold 8 pencils if their actual diameter was more than 6.5 (which is totally possible) eg 7.5mm. what will happen then? the box could not hold 8 pencils. so in order for the box to hold the 8 pencils in ANY CASE, we will take upper bound of the diameter, ie 7.5mm
7.5mm*8 = 60 mm = 6 cm

 

[ashiqbal]

which question?

i mentioned q11!

 

[Amber]

see s_10_qp22 q11 and please explain why in the marking schemes are widths given 2,2,5,5,10 instead of 1,1,2.5,2.5,5 because they have asked for 1 cm = 2 seconds in the question. so have they actually given the range in the ms or the width of each bar?
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_s10_qp_22.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Mathematics D (Calculator Version) (4024)/4024_s10_ms_22.pdf

they hve given the range in seconds for each bar

 

[kitecrystal]

i believe this is the wrong explanation.
they have asked for what? the smallest width that can ALWAYS hold 8 pencils, right? so we have to take the upper bound of the pencils's diameter. this is because if we take the lower bound of the pencils,6.5mm, the box could not hold 8 pencils if their actual diameter was more than 6.5 (which is totally possible) eg 7.5mm. what will happen then? the box could not hold 8 pencils. so in order for the box to hold the 8 pencils in ANY CASE, we will take upper bound of the diameter, ie 7.5mm
7.5mm*8 = 60 mm = 6 cm

thanks for making the correction...

 

[ashiqbal]

thankuuu!! well how to do those questions in wich they ask wat shud b multiplied with a particualar no to make it a perfect square?

give me an example. wait i wil give u one:
2*2*2*3*5 is not a perfect square. it is actually 120. what can we do to make it a perfect square? we must have multiples of two of every factor ie in this case, we need to have 4 twos, 2 threes, and 2 fives
so we will multiply it with 2*3*5 so that it becomes 2*2*2*2*3*3*5*5 = 3600 (60^2)

 

[Haris Bin Zahid]

ashiqbal, syed1995....here is a question: The speed v m/s of a particle travelling from A to B, at time t s after leaving A, is given by v=10t-t^2. The particle starts from rest at A and comes to rest at B. Show that the particle has a speed of 5 m/s or greater for exactly 4√5 s.
Using 10t-t^2.=5, we get 5+2√5 and 5-2√5. The examiner report says to subtract one from the other. Why to do so?