Answer:
40 mph
Step-by-step explanation:
If the speed increased by 20%, now the speed is 120% of the original speed.
48 mph is 120%, so dividing by 6 will get 8 which is 20%.
If 8 is 20%, you can multiply it by 5 to get 40, which is 100%. This means 40 mph is the original speed.
Hope this helps!
Answer:
126
Step-by-step explanation:
Total volume of sand = pi/3*(6^2)*(15) + pi*(6)^2*(30) = 1260*pi mm^3
So it will therefore take 1260*pi/10*pi = 126 seconds for all of the sand from the top hourglass to drip down to the bottom hourglass.
<span>First of all, we need to put commas in the number so it would look less confusing
309 , 099 , 990
Hundred million hundred of thousnd Hundred
So the correct way to say it would be : three hundred nine million ninety nine thousand nine hundred and ninetyHope this helps. Let me know if you need additional help!</span>
ANSWER
x = ±1 and y = -4.
Either x = +1 or x = -1 will work
EXPLANATION
If -3 + ix²y and x² + y + 4i are complex conjugates, then one of them can be written in the form a + bi and the other in the form a - bi. In other words, between conjugates, the imaginary parts are same in absolute value but different in sign (b and -b). The real parts are the same
For -3 + ix²y
⇒ real part: -3
⇒ imaginary part: x²y
For x² + y + 4i
⇒ real part: x² + y (since x, y are real numbers)
⇒ imaginary part: 4
Therefore, for the two expressions to be conjugates, we must satisfy the two conditions.
Condition 1: Imaginary parts are same in absolute value but different in sign. We can set the imaginary part of -3 + ix²y to be the negative imaginary part of x² + y + 4i so that the
x²y = -4 ... (I)
Condition 2: Real parts are the same
x² + y = -3 ... (II)
We have a system of equations since both conditions must be satisfied
x²y = -4 ... (I)
x² + y = -3 ... (II)
We can rearrange equation (II) so that we have
y = -3 - x² ... (II)
Substituting into equation (I)
x²y = -4 ... (I)
x²(-3 - x²) = -4
-3x² - x⁴ = -4
x⁴ + 3x² - 4 = 0
(x² + 4)(x² - 1) = 0
(x² + 4)(x-1)(x+1) = 0
Therefore, x = ±1.
Leave alone (x² + 4) as it gives no real solutions.
Solve for y:
y = -3 - x² ... (II)
y = -3 - (±1)²
y = -3 - 1
y = -4
So x = ±1 and y = -4. We can confirm this results in conjugates by substituting into the expressions:
-3 + ix²y
= -3 + i(±1)²(-4)
= -3 - 4i
x² + y + 4i
= (±1)² - 4 + 4i
= 1 - 4 + 4i
= -3 + 4i
They result in conjugates
Answer:
c
Step-by-step explanation:
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