Answer: A; 6.3%
Step-by-step explanation:
Problem 1
For the first problem, we first want to find y so that we can plug it into the expression.
We can use elimination method for the system of equations to solve.
3x+3y=21
3x-y=5
We subtract both equations to eliminate x.
4y=16 [divide both sides by 4]
y=4
Now that we know y, we can plug it into the expression.
[divide]
[subtract]
We know that the answer is A.
--------------------------------------------------------------------------------------------------------
Problem 2
For the second problem, we need to know how to calculate percent error. The formula for precent error is 
. We know that the exact value is 80 because the buyer was supposed to given 80. 75 is the measured value because that was what the buyer was given.
[subtract]
[solve absolue value]
[divide]
[multiply]
Since the problem said to round to one decimal place, we know that the answer is 6.3%.
Answer:
what is the situation?
Step-by-step explanation:
Answer:
13.2 minutes or 13 minutes 12 seconds.
Step-by-step explanation:
1. Count how much water drains the first pump every minute. Let the volume of pool be D. Every minute first pump drains D/11 water.
2. Working together(6 minutes) First pump drains 6D/11 water, hence the second pump drains 5D/11 water.
3.Count how much water drains second pump per minute -> (5D/11)/6= 5D/66
4. It takes the second pump 66 minutes to drain pool 5 times, thus it takes 13.2(66/5) minutes to drain the pool, which is 13 minutes 12 seconds.
Step-by-step explanation:
given,velocity = 5 m/s
and distance=12×1000=12000m
now,time =?
we have , v=s/t
or, t= s/v
so,t=12000/5
2400sec.....ans
=
