Element X is a radioactive isotope such that every 9 years, its mass decreases by half. Given that the initial mass of a sample
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Answer:
The answer is 21 minutes
Step-by-step explanation:
We use the equation Xf = Xo + vt
1) At 1:00 PM, child one leaves the starting point heading north at a constant velocity of 6 mi/hr or .1 [mi/min] (divide by 60 to convert from [mi/hr] to [mi/min])
2) He walks for 15 minutes before kid 2 starts walking. In 15 minutes he is able to cover 1.5 [mi]
3) Now, child 2 starts walking and we know that when the range reaches 3 miles, they won´t be able to communicate. So the sum of the final position of child 1 and child 2 must be 3[mi]
- Child 1 final position =>
- Child 2 final position =>
4) Sum the equations and equate to 3
5) Substitute the values we already know
6) in 15 + 6 minutes they will be 3miles apart
7) In 21 minutes they will still be able to communicate with one another.
Answer:
The equation that matches the table is y = -5x + 7 ⇒ C
Step-by-step explanation:
The form of the linear equation is y = m x + b, where
- m is the slope of the line
- b is the y-intercept (value y at x = 0)
The rule of the slope is m = , where
- (x1, y1) and (x2, y2) are two points on the line
From the given table
→ Choose any two points from the table
∵ Points (0, 7) and (1, 2) are in the table
∴ x1 = 0 and y1 = 7
∴ x2 = 1 and y2 = 2
→ Substitute them in the rule of the slope above
∵ m =
∴ m = -5
→ Substitute it in the form of the equation above
∵ y = -5x + b
∵ b is the value of y at x = 0
∵ At x = 0, y = 7
∴ b = 7
∴ y = -5x + 7
∴ The equation that matches the table is y = -5x + 7