Answer:
Train A - 50 miles per hour
train B - 30 miles per hour
Step-by-step explanation:
Let x mph be the speed of the train B, then the speed of the train A is (x+20) mph.
In 3 hours,
- train A travels 3(x+20) miles
- train B travels 3x miles
In total, they covered the distance of 240 miles, so
![3(x+20)+3x=240\ \ \ \text{[Divide by 3]}\\ \\x+20+x=80\\ \\2x=80-20\\ \\2x=60\\ \\x=30\ mph\\ \\x+20=30+20=50\ mph](https://tex.z-dn.net/?f=3%28x%2B20%29%2B3x%3D240%5C%20%5C%20%5C%20%5Ctext%7B%5BDivide%20by%203%5D%7D%5C%5C%20%5C%5Cx%2B20%2Bx%3D80%5C%5C%20%5C%5C2x%3D80-20%5C%5C%20%5C%5C2x%3D60%5C%5C%20%5C%5Cx%3D30%5C%20mph%5C%5C%20%5C%5Cx%2B20%3D30%2B20%3D50%5C%20mph)
3(2x-4)=2(x+4)
6x-12=2x+8
6x-2x=8+12
4x=20
x=20/4
x=5
Is point B.
Because √3≈1.7.
So it should be B.
To solve this problem you must apply the proccedure shown below:
1. You have:
<span>
In(2x+3)=7
2. Then, you must apply log(e), as below:
</span><span>
In(2x+3)=ln(e^7)
3. Now, you obtain:
2x+3=e^7
4. Youy must clear the variable "x", as below:
2x=e^7-3
</span> x=(e^7-3)/2
<span>
5. Therefore, the value of "x" is:
x=546.817
</span><span>
The answer is: </span>x=546.817<span> </span>
