Marta has opened a savings account with $25. At the end of three months, she has $85 in her account. She deposited the same amou
nt each month during these three months. At what rate has she been making deposits to her savings?
$25 a month
$25 a week
$20 a month
$20 a week
$25 a month
$25 a week
$20 a month
$20 a week
1 answer:
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9514 1404 393
Answer:
zeros: {-2, 1, 5}
Step-by-step explanation:
A graphing calculator works nicely for identifying turning points, roots, increasing/decreasing intervals, and more.
V1 - velocity first train
v2 - velocity second train
v2 > v1
v2 - v1 = 17 mph
We know, that:
![s_1+s_2=210 \ [miles] \\ \\ t_1=t_2=2h](https://tex.z-dn.net/?f=s_1%2Bs_2%3D210%20%5C%20%5Bmiles%5D%20%5C%5C%20%5C%5C%20t_1%3Dt_2%3D2h)
So:
NOw we've got simple system of equations:
![+\begin{cases} v_2-v_1=17 \\ v_2+v_1=105\end{cases} \\ \\ 2v_2=122 \qquad /:2 \\ \\ v_2=61 \qquad [mph] \\ \\ v_2-v_1=17 \\ \\ 61-v_1=17 \\ \\ v_1=44](https://tex.z-dn.net/?f=%2B%5Cbegin%7Bcases%7D%20v_2-v_1%3D17%20%5C%5C%20v_2%2Bv_1%3D105%5Cend%7Bcases%7D%20%5C%5C%20%5C%5C%202v_2%3D122%20%5Cqquad%20%2F%3A2%20%5C%5C%20%5C%5C%20v_2%3D61%20%5Cqquad%20%5Bmph%5D%20%5C%5C%20%5C%5C%20v_2-v_1%3D17%20%5C%5C%20%5C%5C%2061-v_1%3D17%20%5C%5C%20%5C%5C%20v_1%3D44)
Velocities of these trains are 61mph and 44mph
v2 - velocity second train
v2 > v1
v2 - v1 = 17 mph
We know, that:
So:
NOw we've got simple system of equations:
Velocities of these trains are 61mph and 44mph