Answer:
zjvmNxn
Step-by-step explanation:
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ANSWER
5
EXPLANATION
The equation that expresses the approximate height h, in meters, of a ball t seconds after it is launched vertically upward from the ground is
![h(t) = - 4.9 {t}^{2} + 25t](https://tex.z-dn.net/?f=h%28t%29%20%3D%20%20-%204.9%20%7Bt%7D%5E%7B2%7D%20%20%2B%2025t)
To find the time when the ball hit the ground,we equate the function to zero.
![- 4.9 {t}^{2} + 25t = 0](https://tex.z-dn.net/?f=%20-%204.9%20%7Bt%7D%5E%7B2%7D%20%20%2B%2025t%20%3D%200)
Factor to obtain;
![t( - 4.9t + 25) = 0](https://tex.z-dn.net/?f=t%28%20-%204.9t%20%2B%2025%29%20%3D%200)
Apply the zero product property to obtain,
![t = 0 \: or \: \: - 4.9t + 25 = 0](https://tex.z-dn.net/?f=t%20%3D%200%20%5C%3A%20or%20%5C%3A%20%20%5C%3A%20%20-%204.9t%20%2B%2025%20%3D%200)
![t = 0 \: \: or \: \: t = \frac{ - 25}{ - 4.9}](https://tex.z-dn.net/?f=t%20%3D%200%20%5C%3A%20%20%5C%3A%20or%20%5C%3A%20%20%5C%3A%20t%20%3D%20%20%5Cfrac%7B%20-%2025%7D%7B%20-%204.9%7D%20)
t=0 or t=5.1 to the nearest tenth.
Therefore the ball hits the ground after approximately 5 seconds.
0.9030 > 0.8736
0.9 > 0.8
so your first option is correct
This is fairly simple. Divide 2,871,000 by 10 and that's your answer!
![\frac{2,871,000}{10} =287,100](https://tex.z-dn.net/?f=%20%5Cfrac%7B2%2C871%2C000%7D%7B10%7D%20%3D287%2C100)
Also, since you're dividing by a factor of 10 (or in this case, <em>10</em>) you can just take away as many places as are zeros in the number you're dividing from. This works for <em>10, 100, 1,000, 10,000, etc. </em>In this case, since there is only one zero in 10 you only take away one place marking, which gives you 287,100.
Answer:
45 girls
Step-by-step explanation:
- Remark
- There are only 2 choices for gender. So if the class is 60% girls, the there must be 100 - 60 = 40% for the boys.
- But we are told that the boys are 30 in number.
- Let x = the total number of students.
Solution
- 40/100 * x = 30 Change the % to a decimal
- 0.4 x = 30 Divide both sides by 0.4
- 0.4 x / 0.4 = 30 / 0.4 Do the division
- x = 30/0.4
- x = 75 students in total
Formula
Total of Boys and Girls = Number of boys + number of girls.
Givens
- Total = 75
- Number of boys = 30
Solution II
- 75 = x + 30 Subtract 30 from each side
- 75 - 30 = x +30 - 30
- 45 = x
- There are 45 girls in the class.