Multiply the first equation by -1
-3x-y=-4
2x+y=5
Add them up
-x=1
So x=-1
And y=7
So the first option is correct
Answer:
250 of 65% acid
100 gallons of 30% acid
Really sorry if this is incorrect, I had this question on my Lesson 16 test, and I don't know if it's correct or not...
Let us assume $x is deposit at 2.5% interest.
At the rate 4.5% deposited amount is twice of the amount deposited at 2.5%.
Therefore, at the rate 4.5% deposited amount = $2x.
Total interest earned by both different deposited amount at the rate 2.5% and at the rate 4.5% = $1150.
We can setup an eqation now,
Interest earned on $x at 2.5% + interest earned on $2 at 4.5% = $1150.
2.5% of x + 4.5% of 2x = 1150
Percentage could be written in decimals by dividing by 100.
Therefore, 2.5% = 2.5 /100= 0.025 and 4.5% = 4.5/100 = 0.045.
We could rewrite above equation as,
0.025*x + 0.045 * 2x = 1150
0.025x + 0.09x =1150
Adding 0.025x + 0.09x, we get 0.115x.
So, 0.115x=1150.
Dividing both sides by 0.115.
0.115x/0.115=1150/0.115.
x= $1000.
2x= 2* 1000= $2000
Therefore,
$1000 deposited at 2.5% and $2000 deposited at 4.5%.
Answer:
Part A: The population are the American adult citizens, excluding the ones from Alaska and Hawaii. The population is the people which the sample is trying to represent, as a hole.
The sample is a portion of this population, and in this case is represented by a randomly selected amount of people whose response to the interview has been selected.
Part B: The sample here has been selected in two steps. The first step is the one that we must pay attention to: the numbered list of one million responses from around the US (excluding Alaska and Hawaii). Because these responses were obtained by an online survey, the sample looks like a convenience sampling, as it depends on the availability and willingness from participants to take part of the study (is not compulsory for everyone, so not everyone is going to response, then there are people that is not going to be represented by). The second step is the random selection of a part of the previous responses. This last part will ensure that, the individuals that took part of the group that was interviewed, are well represented in the results.
Part C: As it was mentioned, there is a selection bias, because the information from the sample comes from a specific group of people that has certain features that may not represent all American adults citizens. For example, the opinion of those people who do not use internet, will not be considered (and they may be a large number of persons). This situations weaken the conclusions obtained in the study, as they are not representative of the hole population.
Step-by-step explanation:
Answer:
3
Step-by-step explanation:
mhm for your brother
anyways...
2x-3+6x = 21
Adding like terms
8x -3 = 21
Adding 3 on both sides
8x = 24
Dividing both sides by 8
x = 3
