The first term a = 1,
Common difference, d: 7 - 1 = 6.
a(n) = a + (n -1)d,
For 30th term. = 1 + (30 -1)*6
= 1 + 29*6 = 1 + 174 = 175
In this big ol' word problem, this is just an instance of basic multiplication/division.
If it takes it 1 hour for 3 meters...
12 ÷ 3 = 4.
It would take 4 hours for the water level to change to 12 meters.
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By equating both equations we get :
Answered by : ❝ AǫᴜᴀWɪᴢ ❞
<span>the sum of the first and three times the second is 54.
x + 3y = 54
3y = 54 - x
y= 54 /3 - x / 3 = 18 -x /3
</span>xy = x (18 -x /3) = 18x - x^2 / 3 = - 1/3 x ^ 2 + 18 x
<span>
</span><span>since a<0, it is concave downward, and the vertex is the maximum value. That vertex occurs at x= - b /2a = (-18) / (-2/3) = 12
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<span>The first number is x=12.
The second is y = </span><span>18 -x /3 = 18- 12/ 3 = 18 - 4 = 14 </span>
