Jennifer earned $249.60 in 6 1/2 years on a $640 investment. What was the simple interest rate?
2 answers:
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Answer: 11.6
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Explanation:
See the attached image for a visual reference
The distance from point D to E is 21 units. Point C is the midpoint, so CD is 10.5 units long (21/2 = 10.5)
We have a right triangle ACD. The legs are
AC = 5
CD = 10.5
The hypotenuse is
AD = x
Because AD is another radius of the same circle
Use the pythagorean theorem to find x
a^2 + b^2 = c^2
5^2 + 10.5^2 = x^2
25 + 110.25 = x^2
135.25 = x^2
x^2 = 135.25
x = sqrt(135.25)
x = 11.629703349613
which rounds to 11.6 when rounding to the nearest tenth (one decimal place)
--------------------------------------
Explanation:
See the attached image for a visual reference
The distance from point D to E is 21 units. Point C is the midpoint, so CD is 10.5 units long (21/2 = 10.5)
We have a right triangle ACD. The legs are
AC = 5
CD = 10.5
The hypotenuse is
AD = x
Because AD is another radius of the same circle
Use the pythagorean theorem to find x
a^2 + b^2 = c^2
5^2 + 10.5^2 = x^2
25 + 110.25 = x^2
135.25 = x^2
x^2 = 135.25
x = sqrt(135.25)
x = 11.629703349613
which rounds to 11.6 when rounding to the nearest tenth (one decimal place)
Answer:
a) 40 feet
b) 54 ft/min
c) 4 mins
Step-by-step explanation:
Solution:-
- Kesha models the height ( h ) of the baton from the ground level but thrown from a platform of height hi.
- The function h ( t ) is modeled to follow a quadratic - parabolic path mathematically expressed as:
h ( t ) = −16t² + 54t + 40
Which gives the height of the baton from ground at time t mins.
- The initial point is of the height of the platform which is at a height of ( hi ) from the ground level.
- So the initial condition is expressed by time = 0 mins, the height of the baton h ( t ) would be:
h ( 0 ) = hi = -16*(0)^2 + 54*0 + 40
h ( 0 ) = hi = 0 + 0 + 40 = 40 feet
Answer: The height of the platform hi is 40 feet.
- The speed ( v ) during the parabolic path of the baton also varies with time t.
- The function of speed ( v ) with respect to time ( t ) can be determined by taking the derivative of displacement of baton from ground with respect to time t mins.
v ( t ) = dh / dt
v ( t )= d ( −16t² + 54t + 40 ) / dt
v ( t )= -2*(16)*t + 54
v ( t )= -32t + 54
- The velocity with which Kesha threw the baton is represented by tim t = 0 mins.
Hence,
v ( 0 ) = vi = -32*( 0 ) + 54
v ( 0 ) = vi = 54 ft / min
Answer: Kesha threw te baton with an initial speed of vo = 54 ft/min
- The baton reaches is maximum height h_max and comes down when all the kinetic energy is converted to potential energy. The baton starts to come down and cross the platform height hi = 40 feet and hits the ground.
- The height of the ball at ground is zero. Hence,
h ( t ) = 0
0 = −16t² + 54t + 40
0 = -8t^2 + 27t + 20
- Use the quadratic formula to solve the quadratic equation:
Answer: The time taken for the baton to hit the ground is t = 4 mins