Answer:
y = 8
Step-by-step explanation:
Hello!
We can solve for y by isolating it.
<h3>Solve for y</h3>
- 3y - 15 = y + 1
- 3y - 15 - y = y +1 - y
- 2y - 15 = 1
- 2y - 15 + 15 = 1 + 15
- 2y = 16
- y = 16/2
- y = 8
The value of y is 8.
Answer:
<h3>Option c)

is correct</h3><h3>
The alternate hypothesis for the significance test is 
</h3>
Step-by-step explanation:
The alternate hypothesis use the sumbol for the population value
Let p be the proportion , Mean be
and stadard deviation be 
The null hypothesis states that population value is equal to the value mentioned in the given claim.
(by given).
The alternate hypothesis for the significance test states that the opposite of the null hypothesis(based on the claim )
∴ 
The symbol "<" because we want to test if the maze is completed faster and thus if the time has decreased.
<h3>∴ option c)

is correct.</h3>
Answer:
Bobby around 131 minutes and Billy around 111 minutes
Step-by-step explanation:
To solve the problem it is important to raise equations regarding what happens.
They tell us that Billy (Bi) and Bobby (Bo) can mow the lawn in 60 minutes. That is to say that what they prune in a minute is giving as follows:
1 / Bo + 1 / Bi = 1/60 (1)
They say Billy could mow the lawn only in 20 minutes less than it would take Bobby, therefore
1 / Bi = 1 / (Bo-20) (2)
Replacing (2) in (1) we have:
1 / Bo + 1 / (Bo-20) = 1/60
Resolving
(Bo - 20 + B0) / (Bo * (Bo-20) = 1/60
120 * Bo - 1200 = Bo ^ 2 - 20Bo
Rearranging:
Bo ^ 2 - 140Bo -1200 = 0
Now applying the general equation
Bo = 130.82 or Bo = 9.17, <em>this last value cannot be because Billy took 20 minutes less and neither can he prune faster than the two together</em>, therefore Bobby only takes around 131 minutes and Billy around 111 minutes
Checking with equation 1:
1/131 +1/111 = ~ 1/60
Multiply 190 by 0.27 and you should get your answer