Answer:
3a. 84
3b. 150
Step-by-step explanation:
(3*7)+(3*21)
what is 3*7? it's 21
what is 3*21? it's 63
so 21 + 63 is the answer to the first question :D
10*(8+7)
8+7 first cause it's in parentheses
15
10*15 is equal to 150
The average atomic mass is 6.92X
How do we compute the average atomic mass?
In a bid to calculate the average atomic mass, we multiply the fraction of each isotope by the mass number , then add them together.
This is more like weighted average, as shown below:
average atomic mass=(mass number of first isotope*fraction)+(mass number of second isotope*fraction)
average atomic mass=(6X*7.59%)+(7X*92.41%)
average atomic mass= 6.92X
Find out more about average atomic mass on:brainly.com/question/13299770
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Answer:
Step-by-step explanation:

Answer:
By using the value of cosine function relations, we can easily find the value of sin 120 degrees. Using the trigonometry formula, sin (90 + a) = cos a, we can find the sin 120 value. We know that the value of cos 30 degrees is √3/2. Therefore, sin 120° = √3/2
Step-by-step explanation:
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C, planes are more likely to take off on time. .72 as a percent is 72%. Hence, a relatively high probability that the planes will take of on time.