Answer:
2.4 hours
Step-by-step explanation:
Let total work = X
Rate of work done = X ÷ time
Rate of A = X/4
Rate of B = X/6
If they work together, rate is the sum of their individual rates, i.e.
X/4 + X/6
= (3X + 2X)/12 (taking LCM)
=5X/12
Rate = X/time
5X/12 = X/time
time = X÷(5X/12)
time = X × 12/(5X)
time = 2.4 hours
Shortcut:
Product of individual times/sum of individual times
= (4×6)/(4+6)
=24/10
=2.4 hours
Answer:
Check the explanation
Step-by-step explanation:
Here we have to first of all carry out dependent sample t test. consequently wore goggles first was selected at random for the reason that the reaction time in an emergency taken with goggles would be greater than the amount of reaction time in an emergency taken with not so weakened vision. So that we will get the positive differences d = impaired - normal
b)
To find 95% confidence interval first we need to find sample mean and sample sd for difference d = impaired minus normal.
We can find it using excel that is in the first attached image below,
Therefore sample mean 
= 0.98
Sample sd 
= 0.3788
To find 95% Confidence interval we can use TI-84 calculator,
Press STAT ----> Scroll to TESTS ---- > Scroll down to 8: T Interval and hit enter.
Kindly check the attached image below.
Therefore we are 95% confident that mean difference in braking time with impaired vision and normal vision is between ( 0.6888 , 1.2712)
Conclusion : As both values in the interval are greater than 0 , mean difference impaired minus normal is not equal to 0
There is significant evidence that there is a difference in braking time with impaired vision and normal vision at 95% confidence level .
Answer: 40
Step-by-step explanation: if 8 stops complete 20% of the map 100% is 5 times that so 8x5 is 40 so 40 stops in total
You are trying to find the side between the right angle and the degree (This is known as the adjacent)
You are given degree 42
You also given the longest side of 19 (This is known as the hypothenuse)
Cosine: adjacent/hypothenuse
Cos42 = x/19
0.7431448255 = x/19
x = 19 * 0.7431448255
x = 14.11975168, round to tenth
Solution: x = 14.1
<h2>
Answer:</h2>
cos 28°cos 62°– sin 28°sin 62° = 0
<h2>
Step-by-step explanation:</h2>
From one of the trigonometric identities stated as follows;
<em>cos(A+B) = cosAcosB - sinAsinB -----------------(i)</em>
We can apply such identity to solve the given expression.
<em>Given:</em>
cos 28°cos 62°– sin 28°sin 62°
<em>Comparing the given expression with the right hand side of equation (i), we see that;</em>
A = 28°
B = 62°
<em>∴ Substitute these values into equation (i) to have;</em>
<em>⇒ cos(28°+62°) = cos28°cos62° - sin28°sin62°</em>
<em />
<em>Solve the left hand side.</em>
<em>⇒ cos(90°) = cos28°cos62° - sin28°sin62°</em>
⇒ 0 = <em>cos28°cos62° - sin28°sin62° (since cos 90° = 0)</em>
<em />
<em>Therefore, </em>
<em>cos28°cos62° - sin28°sin62° = 0</em>
<em />
<em />
