t = 0 corresponds to the number of new cars purchased in 1998. If that is so, we can determine t ( time ) by making our quadratic equation here equal to 15,000 - considering that we want the year the number of cars reaches this value. t here is only the number of years to reach 15,000 cars, so we would have to add that value to 1998, to see the year that the cars will reach 15,000.

The " set up " should look like the following quadratic equation -

20t² + 135t + 3050 = 15,000 - Isolate 0 on one side,

20t² + 135t - 11950 = 0 - From here on let us solve using the quadratic equation formula,

$t=\frac{-135+\sqrt{135^2-4\cdot \:20\left(-11950\right)}}{2\cdot \:20}:\quad \frac{-27+\sqrt{38969}}{8}$ ,

$t=\frac{-135-\sqrt{135^2-4\cdot \:20\left(-11950\right)}}{2\cdot \:20}:\quad -\frac{27+\sqrt{38969}}{8}$ ... now as you can see we have two solutions, but time can't be negative, and hence our solution is the first one - about 21.3 years. 1998 + 21.3 = ( About ) The year 2019. Therefore, in the year 2019 the number of new cars purchased will reach 15,000.

3 0

4 years ago

Read 2 more answers

Y=5x+21 and y=-7x-15

topjm [15]

This is a simultaneous system of two linear equations with two unknowns, as the number of unknowns equals the number of equations, we can solve it:
y = 5x + 21
y = -7x - 15
we can equate both equations, given the fact that both are equal to y:
y = y
5x + 21 = -7x - 15
and solving for x:
5x + 7x = -15 - 21
12x = -36
x = -36/12
x = -3
then we substitute this result in the original equation:
y = 5x + 21
y = 5(-3) + 21
y = -15 + 21
y = 6
hence the solution is x = -3 and y = 6

7 0

4 years ago

The distribution of actual weights of 8-ounce wedges of cheddar cheese produced at a dairy is normal with mean 8.1 ounces and st

Brrunno [24]

The mean of the weight is 8.1 ounces.
So the means of the distribution of 10 sample will be 10*8.1.
And the mean of 20 cheese wedges is again 20*8.1.
(The mean of the addition of two normal law is the sum of the
mean of each law)
Divide the above two numbers: $\frac{20\times8.1}{10\times8.1}=2$

The distribution of the sample means of the weights of cheese wedges is multiplied by 2 in the new batches.

7 0

4 years ago