Standard Math Q+A Thread

[jamonwindeyer]

Hey... is anyone able to help me out on how to go about this question?
it refers to the question before which just states what is found in a deck of 52 cards... 4 suits,  each suit has 9 numbers, one ace, and a jack, queen and king...
MANY THANKS!

Hey! So you should try drawing a tree diagram of the three draws, with each draw either yielding a number card or a non-number card. Remember the probabilities will change on the second and third draws because this is without replacement!

Then you just use the tree diagram like normal to solve. Multiply along the relevant branches. So, for example, the probability of zero number cards is just the product of the probabilities along that single branch:



You'll need to add the probabilities of a few branches to calculate the probability of holding two number cards, but hopefully this gives you the idea! Let us know how you travel

[Shadowxo]

Sure! So the dimensions of that big prism of marshmallows can be found by clever adding of the dimensions, it is 20cm by 15cm by 6cm, see if you can spot how they line up. The volume is:



But that's counting the gaps as well - The volume of the marshmallows is just the 24 times the volume of the cylinder. Remember the radius is half the diameter:



Multiply by 24 to get the total marshmallow volume:



And the difference between the two is your answer - The gaps where the chocolate will go

Wouldn't that include the 'gaps' outside the marshmallow cake (but within the rectangle) where the chocolate doesn't go?

Area of one of the chocolate bits = area of one of the 5x5 squares - area of one circle (as there are four quarter-circles per 'square')
= 5*5 - π*2.5² = 5.365 cm²
Volume of one of the chocolate bits = area*height = 5.365*6 = 32.19 cm³
Volume of all 6 chocolate bits = 6*32.19=193.1 cm³

Alternatively, you could just halve the answer Jamon got, as that would be the volume of 12 of the chocolate bits instead of 6

[themangopomegranate]

Hello there, can someone please help me with these questions? I never quite understood random samples and how to use them to solve questions😅 - like how do i generate random numbers on my calculator? *question b onwards 😊

[jamonwindeyer]

Wouldn't that include the 'gaps' outside the marshmallow cake (but within the rectangle) where the chocolate doesn't go?

Area of one of the chocolate bits = area of one of the 5x5 squares - area of one circle (as there are four quarter-circles per 'square')
= 5*5 - π*2.5² = 5.365 cm²
Volume of one of the chocolate bits = area*height = 5.365*6 = 32.19 cm³
Volume of all 6 chocolate bits = 6*32.19=193.1 cm³

Alternatively, you could just halve the answer Jamon got, as that would be the volume of 12 of the chocolate bits instead of 6

Ahh too clever, thanks for the correction Shadow!

[jamonwindeyer]

Hello there, can someone please help me with these questions? I never quite understood random samples and how to use them to solve questions😅 - like how do i generate random numbers on my calculator? *question b onwards 😊 (Image removed from quote.)

A random sample is just a way to guess stuff about your population using a small, randomly selected subset. EG, guessing the average height of all 20 year old males by looking at the height of a few 20 year old males.

Take a random sample of \(n=5\) to be the top 5 people in that table. Persons 1-5. It could be any five people!

Of those 5, 2/5=40% drive a car, 2/5=40% catch a bus, and 1/5=20% walk. This is data from our sample, and if we compare it to the total percentage for the population:

20% walk
40% drive
40% bus

It is actually identical - So in this case, our sample does a fantastic job as an estimate, we got lucky! But different samples will be slightly less effective, purely based on chance

[themangopomegranate]

A random sample is just a way to guess stuff about your population using a small, randomly selected subset. EG, guessing the average height of all 20 year old males by looking at the height of a few 20 year old males.

Take a random sample of \(n=5\) to be the top 5 people in that table. Persons 1-5. It could be any five people!

Of those 5, 2/5=40% drive a car, 2/5=40% catch a bus, and 1/5=20% walk. This is data from our sample, and if we compare it to the total percentage for the population:

20% walk
40% drive
40% bus

It is actually identical - So in this case, our sample does a fantastic job as an estimate, we got lucky! But different samples will be slightly less effective, purely based on chance

Ahhh that's makes so much more sense, thank you so much ! For some reason I always thought it was something more complex 😅

[jamonwindeyer]

Ahhh that's makes so much more sense, thank you so much ! For some reason I always thought it was something more complex 😅

Hate when things get over-complicated! Glad I could help - Good luck in your exam tomorrow (if you are in Year 12, aha)

[morning_sunshine]

Hey
So this is probs easier than I think it is but I think my mind is turning off and just doesnt want to work anymore but I'm pushing through ahahah
 

Anyway, how would i find the distance for this

BTW soz for that TMI

[themangopomegranate]

Hate when things get over-complicated! Glad I could help - Good luck in your exam tomorrow (if you are in Year 12, aha)

😁😁 Yes I have the exam tomorrow and thank you, again !!

[jamonwindeyer]

Hey
So this is probs easier than I think it is but I think my mind is turning off and just doesnt want to work anymore but I'm pushing through ahahah
 

Anyway, how would i find the distance for this

BTW soz for that TMI

Hey! So the angle of depression is 42 degrees, but that appears ABOVE the line in the triangle. The way this works though is that the 42 degree angle of depression appears in the bottom angle of the triangle, at the buoy - Is this something you are familiar with happening?

If so, it is easy. Use the tan ratio (SOHCAHTOA!):



Multiply by \(d\):



Then divide by tan and calculate:



Does this help?

[morning_sunshine]

Hey! So the angle of depression is 42 degrees, but that appears ABOVE the line in the triangle. The way this works though is that the 42 degree angle of depression appears in the bottom angle of the triangle, at the buoy - Is this something you are familiar with happening?

If so, it is easy. Use the tan ratio (SOHCAHTOA!):



Multiply by \(d\):



Then divide by tan and calculate:



Does this help?

Yes this helps so so much!

Honestly don't know how I didn't remember this

Gosh really hope my brain is on the ball tomorrow

THANK YOU SO SO MUCH! LIFESAVER

[jamonwindeyer]

Yes this helps so so much!

Honestly don't know how I didn't remember this

Gosh really hope my brain is on the ball tomorrow

THANK YOU SO SO MUCH! LIFESAVER

Stay relaxed, underline key terms in the question - It will come to you as you need it! Good luck!

[morning_sunshine]

Stay relaxed, underline key terms in the question - It will come to you as you need it! Good luck!

THANK YOU!
I'll be sure to check in with you after the exam

Best advice ever hoenstly!
THANKS SO MUCH HONESTLY DON'T KNOW WHERE I WOULD BE WITHOUT YOUR HELP

[emilybrooks99]

How do we calculate the correlation coefficient? I've tried to find it in my textbook but i've had no luck

[[MA165]]

How do we calculate the correlation coefficient? I've tried to find it in my textbook but i've had no luck

Generally its calculated from a range of data with x and y variables.... which is where the calculator come handy... this is just how i have learnt to do it ... so basically with the x and y data.. enter it into the calculator (on stats mode, select 2: (a+b X)- gives you a table)
and once you have entered in the data press AC then shift 1, then 5 (reg) then 3 (r)... somewhat of a process.... but that should do it...
ATB