BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

DS with proportions!

Expert replies
by ern5231 » Wed Aug 19, 2009 5:13 pm
Three flowers R,C and I are planted in the quantity 1:3:4. Total price of which plantation is the highest?

(1) The price proportion of R,C and I is 1:6:2
(2) R is 0.75 cents more expensive than C and R is 0.25 cents cheaper than I
Join the discussion
Source: — Data Sufficiency |

by eric.gordon884 » Thu Aug 20, 2009 6:12 am
If n flowers of type R are planted then plantation C has 3n flowers and plantation I 4n flowers.

say price of flower R is r.

(i) price of flowers is r,6r, and 2r respectively. Hence price of plantations is rn, 18rn, and 8rn. Plantation C is the most expensive. Sufficient

(ii) price of flowers is r, r-0.75, and r+0.25 respectively. Hence price of plantations is rn, 3n(r-0.75), and 4n(r+0.25). Dropping the n I got r, 3r-2.25, and 4r+1. This is not enough to determine which is most expensive (try diff numbers). Insufficient.

Answer is A.
Join the discussion

by PussInBoots » Thu Aug 20, 2009 11:39 am
eric.gordon884 wrote: (ii) price of flowers is r, r-0.75, and r+0.25 respectively. Hence price of plantations is rn, 3n(r-0.75), and 4n(r+0.25). Dropping the n I got r, 3r-2.25, and 4r+1. This is not enough to determine which is most expensive (try diff numbers). Insufficient.
Obviously r>0, then 4r+1 > r and 4r+1 > 3r - 2.25

Answer is D
Join the discussion

by adamsmith2009 » Sat Aug 22, 2009 6:04 pm
I don't understand how is I the greatest in statement 1? If you take price*quantity wouldn't C be the greatest?

Statement 2 clearly states that I is the greatest.
Join the discussion

by shanrizvi » Sun Aug 23, 2009 2:12 pm
adamsmith2009, lets take statement 1 and statement 2 separately (meaning when we're assessing statement 1, it doesn't matter what statement says. In fact, for us, statement 2 doesn't exist).

Statement 1: Price proportion R:C:I = 1:6:2

The question tells us that the quantity proportion R:C:I = 1:3:4 and asks us for the flower with the highest price*quantity proportion (total price : price*quantity). Note: if you have the price and quantity ratios, you can calculate the total price ratio. Rp*Rq:Cp*Cq:Ip*Iq

Hence, the total price ratio R:C:I will be 1:18:8

Statement 1 is sufficient.

Lets come to statement 2 now.

Statement 2: R is 0.75 cents more expensive than C and R is 0.25 cents cheaper than I

You don't even need to do any calculation for this statement. They've given the relationship between the prices in absolute terms which means that the relationship between the total prices depends on the actual value of R. The statement is insufficient.

It says that R=C+0.75 and R=I-0.25. If R=1, C=0.25 and I=1.25, making the total price ratio 1 : 0.75 : 5 . However, if R=10, C=9.25 and I=10.25, making the total price ratio 10 : 27.75 : 41 .

Note: The total price ratio is calculated using Rp*Rq:Cp*Cq:Ip*Iq.

As you can see, the two examples are not consistent. Hence, the statement is insufficient.
Join the discussion

by mehravikas » Tue Aug 25, 2009 2:03 am
I don't that we can rule out statement 2 because taking different values of R yield different results.

R = c + 3/4
R = I - 1/4

Pick R = 1, therefore C = 1/4, I = 5/4
Quantity = 8
total cost: 1:3/4:5

Pick R = 2, therefore C = 5/4, I = 9/4
Quantity = 8
total cost: 2:15/4:9

Both equations yield different values but highest plantation cost is for I.
shanrizvi wrote:adamsmith2009, lets take statement 1 and statement 2 separately (meaning when we're assessing statement 1, it doesn't matter what statement says. In fact, for us, statement 2 doesn't exist).

Statement 1: Price proportion R:C:I = 1:6:2

The question tells us that the quantity proportion R:C:I = 1:3:4 and asks us for the flower with the highest price*quantity proportion (total price : price*quantity). Note: if you have the price and quantity ratios, you can calculate the total price ratio. Rp*Rq:Cp*Cq:Ip*Iq

Hence, the total price ratio R:C:I will be 1:18:8

Statement 1 is sufficient.

Lets come to statement 2 now.

Statement 2: R is 0.75 cents more expensive than C and R is 0.25 cents cheaper than I

You don't even need to do any calculation for this statement. They've given the relationship between the prices in absolute terms which means that the relationship between the total prices depends on the actual value of R. The statement is insufficient.

It says that R=C+0.75 and R=I-0.25. If R=1, C=0.25 and I=1.25, making the total price ratio 1 : 0.75 : 5 . However, if R=10, C=9.25 and I=10.25, making the total price ratio 10 : 27.75 : 41 .

Note: The total price ratio is calculated using Rp*Rq:Cp*Cq:Ip*Iq.

As you can see, the two examples are not consistent. Hence, the statement is insufficient.
Join the discussion

by kbharadwaj.1987 » Tue Aug 25, 2009 5:03 am
The answer is quite obviously D. :D
Join the discussion

by vikram_k51 » Wed Aug 26, 2009 4:17 am
Will be D.
Join the discussion