SC mathematics Marathon (2 Viewers)

[bleakarcher]

Let Opposite side = 4a
Let Adjacent side = 3a
(sinx=4a/3a=4/3)

(4a)^2+(3a)^2=32^2

16a^2+9a^2= 1024

25a^2=1024

a^2=1024/25

sqrt(a^2)=sqrt(1024/25)

a=32/5

4a= 25.6

:. the opposite side is 25.6 cm

There are probably easier ways to do this, but I like to solve it my way.

Take an isosceles triangle
Draw a line from one vertex to the midpoint of the opposite side
Do so for all 3 vertices
Now Prove the 3 lines you drew are all equal in length

sin(x)=Opp./Hyp.=/=Opp./Adj.

 

[dionb2014]

draw a tree diagram of the possible results for 1st spin. Then accumulate the possible results with the next spin.

1-2,5,8
7-14,8,10,11
3-6,7,10,4
4-7,8,11,5

8 is the most frequent and I know I explained that quite badly.

 

[Sy123]

can someone explain this please?

Assuming all integers have equal possibility:

Possibilities:
1+1 =2
1+3 =4
1+4 =5
1+7 =8

3+3 =6
3+4 =7
3+7 =10

4+4 =8
4+7 =11

7+7 =14

Now if you look at these scores, you will find the mode to be 8
Not a very mathematical way of doing this question, but hey, its multiple choice

 

[dionb2014]

Tom and Bill hunted sheep in a ratio of 10:2
if all together they killed 144 sheep. How many did bill kill?

 

[Sy123]

FIRST ATTEMPT AT THIS QUESTION WAS WRONG
Im so stupid, this question is incredibly simple

let a=opposite

a/32=4/3

3a=128
a=128/3

sin(x)=Opp./Hyp.=/=Opp./Adj.

Fixed

Tom and Bill hunted sheep in a ratio of 10:2
if all together they killed 144 sheep. How many did bill kill?

For every 12 sheep killed, Tom killed 10 and Bill killed 2
:. For every 144 sheep killed, Tom killed 120 and Bill killed 24

 

[knxd]

draw a tree diagram of the possible results for 1st spin. Then accumulate the possible results with the next spin.

1-2,5,8
7-14,8,10,11
3-6,7,10,4
4-7,8,11,5

8 is the most frequent and I know I explained that quite badly.

Assuming all integers have equal possibility:

Possibilities:
1+1 =2
1+3 =4
1+4 =5
1+7 =8

3+3 =6
3+4 =7
3+7 =10

4+4 =8
4+7 =11

7+7 =14

Now if you look at these scores, you will find the mode to be 8
Not a very mathematical way of doing this question, but hey, its multiple choice

Thanks!

 

[RealiseNothing]

FIRST ATTEMPT AT THIS QUESTION WAS WRONG
Im so stupid, this question is incredibly simple

let a=opposite

a/32=4/3

3a=128
a=128/3

Opposite side can't be greater than the hypotenuse, question doesn't work.

 

[nazfiz]

Tom and Bill hunted sheep in a ratio of 10:2
if all together they killed 144 sheep. How many did bill kill?

Adding the ratios together gives you 12
144/12= 12
hence 12 sheep equal one portion
so Bill's amount is given by
2x 12= 24

 

[dionb2014]

Thanks, of course it doesn't work. I must have inverted the fraction.

 

[RealiseNothing]

A harder probability question, but why not:

I have a hat filled with all the prime numbers between 1 and 15. What is the probability that if I pick out 2 numbers and multiply them, the result will be an even number.

 

[friiedrice]

2010 sc
q83 (C) (ii)
tyy

 

[Sy123]

A harder probability question, but why not:

I have a hat filled with all the prime numbers between 1 and 15. What is the probability that if I pick out 2 numbers and multiply them, the result will be an even number.

Product of two odd numbers are always odd
2 is the only series that applies
However repetition does not count because you are taking balls out of the bag
The number of possibilities = 6! (6x5x4x3x2x1)
Number of possibilties without repetition = 6!-6
=714

Number of 2 series that does not repeat = 5
:. 5/714 is the probability of drawing an even number out of the bag

Im either completely right or just plain wrong (I have a feeling its the latter)

 

[nazfiz]

2010 sc
q83 (C) (ii)
tyy

ABCD is a kite.
The area of a kite is given by 1/2xy (x and y being diagonals)
so from multiply the answer from part i by two to gain the area of the entire kite. so
168= 1/2x 25 x BD
BD= 13.44

 

[bleakarcher]

Product of two odd numbers are always odd
2 is the only series that applies
However repetition does not count because you are taking balls out of the bag
The number of possibilities = 6! (6x5x4x3x2x1)
Number of possibilties without repetition = 6!-6
=714

Number of 2 series that does not repeat = 5
:. 5/714 is the probability of drawing an even number out of the bag

Im either completely right or just plain wrong (I have a feeling its the latter)

lol dude, i did it the long way and got 1/3

 

[lath]

i agree - answer = 1/3

 

[dionb2014]

What equipment are you guys bringing to the exam?

 

[applepopper]

hi guys
noob question how do i post an image im trying to get this question up

 

[Sy123]

lol dude, i did it the long way and got 1/3

Damn it, I always do something wrong somehow. Ill redo it because I think Ive seen where my logic has gone wrong.
Prime Numbers (Reference): 2, 3, 5, 7, 11, 13
(The next paragraph is a personal note)
When you select the first ball, the probability of getting a particular ball is 1/6, then second ball you draw out is 1/5. If I wanted to draw the ball 2 and 3 for instance, then the probability of that is 1/30 (6x5)
Probability of any combo that has 2 in it is: 5/30 = 1/6

Therefore the probability is 1/6?

Please show me how you did it

 

[lath]

Damn it, I always do something wrong somehow. Ill redo it because I think Ive seen where my logic has gone wrong.
Prime Numbers (Reference): 2, 3, 5, 7, 11, 13
(The next paragraph is a personal note)
When you select the first ball, the probability of getting a particular ball is 1/6, then second ball you draw out is 1/5. If I wanted to draw the ball 2 and 3 for instance, then the probability of that is 1/30 (6x5)
Probability of any combo that has 2 in it is: 5/30 = 1/6

Therefore the probability is 1/6?

Please show me how you did it

you forgot 3,2; 5,2; 7;2 etc.

 

[Sy123]

you forgot 3,2; 5,2; 7;2 etc.

I had the impression that
2;3 is the same as 3;2 etc.?
If so then Im probably right, if not then you are right