Answer:
46 minutes
Step-by-step explanation:
Sorry about not answering your question sooner, but here is your answer:
In order to get the answer, we have to subtract the original amount of money on the phone card by the amount left ver after the call:
15 - 6.72 = 8.28
Then, we divide this number by 0.18:
8.28 / 0.18 = 46
So, Tammy's call lasted 46 minutes
Hope this helps :)
Let's start from what we know.
Note that:
(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first
with only positive trems (squares of even numbers) and second
with negative (squares of odd numbers). So:
And now the proof.
1) n is even.
In this case, both
and
have
terms. For example if n=8 then:
Generally, there will be:
Now, calculate our sum:
So in this case we prove, that:
2) n is odd.
Here,
has more terms than
. For example if n=7 then:
So there is
terms in
,
terms in
and:
Now, we can calculate our sum:
We consider all possible n so we prove that:
Answer: >72
Step-by-step explanation:
x*1/3-6=<18
1/3*x=<24
x=<72
Christine is more than 72 years old
Answer:
31
Step-by-step explanation:
The mean is the average so you add all the numbers together (186) and divide by how many numbers there are (6)