first off, I'd like to point out that for the 5th test, he has 96, and that's +6 above 90, and therefore it should be 6.
if all the above/below numbers, summed up yield 0, that simply means the average is an even 90 on average for all 6 tests, if they yield above 0, is above on the average, and if it's below 0, a negative value, he needs to do more work.
-7+4-11+7+6-3 = -4.
you can think of it this way, if he had 90 on all 6 tests, the above/below row will show 0, 0, 0, 0, 0, 0. If any of the tests was above 90, that row will yield a sum more than 0, and if any of the tests were below, that sum will be a negative value.
Given a series, the ratio test implies finding the following limit:

If r<1 then the series converges, if r>1 the series diverges and if r=1 the test is inconclusive and we can't assure if the series converges or diverges. So let's see the terms in this limit:

Then the limit is:

We can simplify the expressions inside the absolute value:

Since none of the terms inside the absolute value can be negative we can write this with out it:

Now let's re-writte n/(n+1):

Then the limit we have to find is:

Note that the limit of 1/n when n tends to infinite is 0 so we get:

So from the test ratio r=0.4 and the series converges. Then the answer is the second option.
422.72 is your answer vote me brainliest if you liked it
Answer:
Yes
Step-by-step explanation:
Answer:
Step-by-step explanation:
10x+ 150=220 is the equation for the second plan you subtract 150 from 220 to get 70 and divide that by 10 and you get 7 which is the number of weeks it'll take
220/25=x
So for this one it'll take 8.8 weeks to get enough money and you divide 220 by the amount which is 25 to get 8.8 the number of weeks I'll take
I dont understand what the second one is asking so sorry dude but I think that's right