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Mixture Problem: GMAT, GRE



24 lbs of coffee P and 25 lbs of coffee V are mixed to make coffee X and Y. The ratio of P to V in coffee X is 4 to 1, in Y is 1 to 5. How much of P is contained in the mixture X?


A. 10
B. 20
C. 30
D. 40
D. 45




Make Coffee X and Coffee Y
P:V in coffee X is 4:1
P:V in coffee Y is 1:5

X + Y = 49

System of Equations

P1 + V1 = X (eq.1)
P2 + V2 = Y (eq.2)

P1 + P2 = 24 (eq.3)
V1 + V2 = 25 (eq.4)

P1 = (4/5)x
P2 = (1/6)y

V1 = (1/5)x
V2 = (5/6)y

---


(4/5)x + (1/6)y = 24
(1/6)y = 24 - (4/5)x

y = 144 - (24/5)x

(1/5)x + (5/6)y = 25


---

(1/5)x + (5/6)(144 - (24/5)x) = 25
(19/5)x = 95
x = 25

---

Y = 49 - x
Y = 24

---

P1 = (4/5)(25) = 20
P2 = (1/6)(24) = 4

Jeremiah LaBrash

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