Use the diagram of a T with an arrow, as shown.
1 answer:
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Answer:
the 8% loan has a principal of $37500
the 12% loan has a principal of $12500
Step-by-step explanation:
Let's start by writing the general equation for the interest hwre I is the interest, P is the principal (in our case would be loan amounts), "r" is the interest rate in decimal form (in our case one would be 0.12, and the other one 0.08), and t is the time in years (in our case 1 year).
Then we write the interest equation coming from each loan at the end of this year (we call I1 the interest coming from the 12% loan and I2 the interest coming from the 8% one). Since we don't know the loan amounts (in fact those are what we need to find) we will name one "x" and the other "y":
Next, we add these last two equations term by term, and replace the addition of both interests by $4500 as given in the information:
This is our first equation in the variables x and y which are our unknowns.
Now we generate the second equation on x and y by writing in agebraic terms the other piece of information we have: "the total of the two loans is $50000. That is the addition of the principals x and y should equal $50000:
We solve for y in this last equation and replace its form in terms of x in the equation of the interest, and solve for the unknown x:
Therefore the amount of the loan at 12% is $12500
Now to find the amount of the second loan "y" we use the equation for the totals of the loans:
Therefore, the loan at 8% is $37500
Answer: third option 268.8
Explanation:
For this kind of proble it is very important that you attach the figure because it contains important information to understand the question.
I have attached the figure for better understanding.
1) The top portion (and the bottom is congruent but rotated 180°) of the hourglass is a figure equivalent to a cylinder on top and a cone on bottom.
So the total volume contained in the top portion is the volume of a cylinder + the volume of a cone.
This is how you calculate the volume of the top portion:
1) The height of the cylinder is 54 mm - 18 mm = 36 mm
2) The formula for the volume of a cylinder is V = π (radius)^2 * height
radius = 8 mm
height = 36 mm
=> V = π(8mm)^2 * 36 mm = 2304π (mm)^3
3) The formula for the volume of a cone is V = (1/3)π(radius)^2 * height
radius = 8 mm
height = 18 mm
V = (1/3)π(8mm)^2 * 18 mm = 384π (mm)^3
4) The total volume of the top portion is volumen of the cylindrical part + voume of the cone:
Total voluem = 2304π (mm)^3 + 384π (mm)^3 = 2688π (mm)^3
5) To find the number of seconds <span>it take until all of the sand has dripped to the bottom of the hourglass you have to divide the total volumen of sand by the rate:
time in seconds = total volume of sand / rate of dripping
time in seconds = [2688 π (mm)^3 ] / [10π (mm)^3 / s] = 268.8 s
That is the answer: 268.8 s
</span>
Explanation:
For this kind of proble it is very important that you attach the figure because it contains important information to understand the question.
I have attached the figure for better understanding.
1) The top portion (and the bottom is congruent but rotated 180°) of the hourglass is a figure equivalent to a cylinder on top and a cone on bottom.
So the total volume contained in the top portion is the volume of a cylinder + the volume of a cone.
This is how you calculate the volume of the top portion:
1) The height of the cylinder is 54 mm - 18 mm = 36 mm
2) The formula for the volume of a cylinder is V = π (radius)^2 * height
radius = 8 mm
height = 36 mm
=> V = π(8mm)^2 * 36 mm = 2304π (mm)^3
3) The formula for the volume of a cone is V = (1/3)π(radius)^2 * height
radius = 8 mm
height = 18 mm
V = (1/3)π(8mm)^2 * 18 mm = 384π (mm)^3
4) The total volume of the top portion is volumen of the cylindrical part + voume of the cone:
Total voluem = 2304π (mm)^3 + 384π (mm)^3 = 2688π (mm)^3
5) To find the number of seconds <span>it take until all of the sand has dripped to the bottom of the hourglass you have to divide the total volumen of sand by the rate:
time in seconds = total volume of sand / rate of dripping
time in seconds = [2688 π (mm)^3 ] / [10π (mm)^3 / s] = 268.8 s
That is the answer: 268.8 s
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