ratio of the volumes

[sanju09]

The value of a substance P is half the sum of the volumes of substance Q and R, and the volume of substance Q is 20 percent of the sum of the volumes of substances P and R. What is the ratio of the volumes of substance R to the sum of the volumes of substance P and Q?
(A) 1/4
(B) 1/3
(C) 2/5
(D) 3/4
(E) 1

[pradeepkaushal9518]

ans is E

p=(Q+R)/2

Q=(p+R)/5

soving we get p/q=2

hence R/p+q

we get 1

[clock60]

also got E-1 but a little bit confused with word value in the start of the problem. is it a typo and must be read volume instead?

[gmatmachoman]

also got E-1 but a little bit confused with word value in the start of the problem. is it a typo and must be read volume instead?

yeah it has to be "volume"...

[shashank.ism]

The value of a substance P is half the sum of the volumes of substance Q and R, and the volume of substance Q is 20 percent of the sum of the volumes of substances P and R. What is the ratio of the volumes of substance R to the sum of the volumes of substance P and Q?
(A) 1/4
(B) 1/3
(C) 2/5
(D) 3/4
(E) 1

P = (Q+R)/2 ..........................(i)
Q = 0.20(P+R).......................(ii)
from i & ii
P = (0.20(P+R) + R)/2 = 0.10 P +0.60 R --> 0.90 P = 0.60 R --> P = 2/3 R
from (ii) Q = 0.20 (P+R) = 0.20 (2/3 R + R) = R/3

Ratio of R to the sum of volumes of P and Q = R/(P+Q) = R/(2/3 R +1/3 R) = 1 AnsE

[shashank.ism]

yeah here the word "value" has no meaning ..it will be surely "volume".

[sanju09]

Read it like "The volume of a substance P is half the sum of the volumes of substance Q and R," or shall I edit, mates?