A bag contains 18 blocks numbered 1 to 18. Two blocks are selected from the bag at the same time.
Let event E = the two numbers do NOT differ by 11
How many outcomes are in the compliment of E?

A) 7
B) 14
C) 292
D) 299

Question

A bag contains 18 blocks numbered 1 to 18. Two blocks are selected from the bag at the same time.
 Let event E = the two numbers do NOT differ by 11
How many outcomes are in the compliment of E? 

A) 7
B) 14
C) 292
D) 299

amistre64 · Answer

what defines a complement?

anonymous · Answer

the outcomes that are not the event?

amistre64 · Answer

right,  so what would you says is all the events that DO differ by 11?

anonymous · Answer

like 18-7 = 11

amistre64 · Answer

18 - 11
17 - 11
16 - 11
15 - 11
14 - 11
13 - 11
12 - 11
11 - 11 <-- the blocks arent the same are they so this is our limitation

7 cases, but whats the flaw if we stop here?

amistre64 · Answer

the same events can be gotten if we pull the blocks out one by one

18  then  7 is one event
7 then 18 is a seperate event

but we have only counted 1 of these events in the process so far.  right?

amistre64 · Answer

7 cases, each case has 2 valid events.  for a total of how many events?

anonymous · Answer

Oh okay so that's what the problem meant by "differ by 11" ok so there are a total of 14 events?

amistre64 · Answer

correct

anonymous · Answer

Thanks so much! :)

amistre64 · Answer

good luck :)  if theres a non mechanical approach to this, something more formulaic i have no idea what it would be

anonymous · Answer

Thanks! Do you think you could help me on another problem?

amistre64 · Answer

help or hurt ... either way

anonymous · Answer

hhaha
If the length of the minute hand of the clock in London commonly known as "Big Ben" is 11.25' from the center of the clock to the tip of the hand, what is the area swept out by the minute hand as it moves 5 minutes of time? 
A) 10.55 ft^2 
B) 28.13 ft^2
C) 33.13 ft^2
D) 66.27 ft^2

amistre64 · Answer

had to do some mod work ...

amistre64 · Answer

we have part of a circle, what portion of the circle are we concerned about?

amistre64 · Answer

the hour markers on a clock face are 5 minutes apart ... 

from 12 to 1 is 5 minutes,  hence  1/12 of the circle is what we want

amistre64 · Answer

what is 1/12 of the area of the full circle?

anonymous · Answer

30 degrees

amistre64 · Answer

forget about degrees, its immaterial

we want 1/12 of the property of the full circle right?  whats the area of the full circle?

amistre64 · Answer

360/12 = 30 degrees yes  but that is just making more work

anonymous · Answer

wait i think the answer is 33.13 ft^2?

amistre64 · Answer

it is :)

1/12  pi (11.25)^2 is about 33.13

anonymous · Answer

THANKS A BUNCH!

amistre64 · Answer

good luck

anonymous · Answer

thank you!