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given:
= cost of Brazilian coffee in mixture
= cost of Venezuelan coffee in mixture
= cost of mixture
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Now I can rite these equations:
(1)
(2)
Multiply both sides of (2) by and
subtract from (1)
(1)
(2)
and, since
288 kg of Brazilian coffee and 96 kg of Venezuelan coffee are needed
The surface area of a sphere of radius r is A = 4π*r^3.
Since the radius in this case is 7 cm (half the 14 cm diameter), the area of this sphere is
A = 4π(7 cm)^2, or 196π cm^2.