In a box the number of blue counters and the number green counters are in the ratio 7:4. The number of green counters and the number of red counters are in the ratio 3:1. The total number of counters in the bag is 444. How many green counters are in the bag?
Number of green counters is 144
Please refer to the attached image for explanations
first, we define the variables:
x: number of years after 1950
f (x): amount of vinyl sold.
then, with the variables defined, we have:
68594 vinyl records were sold in 1958 > f (8) = 68594
91299 vinyl records were sold in 1961 > f (11) = 91299
38720 vinyl records were sold in 1952 > f (2) = 38720
161743 vinyl records were sold in 1967 > f (17) = 161743
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we are told that the revenue is
this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.
so in this case, we have a=−10 and b=4080, so the x-value of the vertex is