median: The number that occurs in the middle after arranging in ascending order of magnitude
;13 13
since both appeared in the middle,you add it and divide by 2
13+13/2
26/2
13
;The median is 13
1) This is a combination, so use ⁴⁰C₂.
⁴⁰C₂ = 780
There are 780 handshakes in total.
2) I got my solution by using the combinations formula. Or another way you could do this is to add up... 39 + 38 + 37 + 36 + 35 + 34 + 33 + 32 + 31... +1. You will end up with 780 (I did this to double check my work).
3) The quickest way to figure this out if Drake invited 1,000 people is to use the natural numbers formula = n(n+ 1)/2.
Plug the numbers in: 999(1000)/2 = 499,500
If Drake invited 1,000 people, there would be 499,500 handshakes.
Answer:
-1
This is because in negative the numbers the higher the number, the lower its value
Step-by-step explanation:
The sum of their speeds is 380 miles per hour. The difference of their speeds is 30 miles per hour. Then the faster plane is traveling at
.. (380 +30)/2 = 205 miles per hour
The slower plane's speed is 30 miles per hour less, so it is traveling at
.. 205 mph -30 mph = 175 miles per hour
ANSWER

EXPLANATION
The explicit rule for an arithmetic sequence is given by:

It was given that:

and

The common difference is

We plug in the values into the explicit formula to get,

Expand to get,

The explicit rule is
