we have been asked to find the sum of the series
As we know that a geometric series has a constant ratio "r" and it is defined as
The first term of the series is 
Geometric series sum formula is
Plugin the values we get
On simplification we get
Hence the sum of the given series is 
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)
Answer:
If we call our unknown value x, then we can say that
The "product of 4 and a number" is 4x
The "difference between" 4x and 6 is 4x - 6
Step-by-step explanation:
Answer:
550km/h
Step-by-step explanation:
v (speed) = d/t
v = 1375/2.5
v =550
The answer is: [B]: "arithmetic" .
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"The <u> arithmetic </u> average ignores compounding."
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