If 175 billion French francs is equivalent to 35 billion United States

Question

If 175 billion French francs is equivalent to 35 billion United States dollars, which of the following expressions represents the number of United States dollars equivalent to f French francs?

(A) f - 140
(B) 5f
(C) 7f
(D) f/5
(E) f/7

PS07453

The OE starts with "In this solution it is assumed that 1 billion = 109. However,
only minor modifications in the first three steps are needed (replace each appearance
of 10^9 with 10^12)". 
 
What do they mean by that and why is that important for the question at all. 
It confused me. Btw. I feel the "109" ought to be "10^9" but they misspelled it.

Millions has six zeros and billions has nine. And both numbers are given in "billions" so we
can ignore that completely anyway.

I will post OA separately but would be good to know why they wrote this. Supposedly,
everything has a reason.

(Small point: Source is not OG but Official GMATPrep Software)

BabySmurf · Accepted Answer

175 billion French francs = 35 billion USD Ignore billion

175 French francs = 35 USD divide by 5

35 French francs = 7 USD divide by 7

5 French francs = 1 USD divide by 5

1 French francs = 1/5 USD

f  is just a variable. They could have written x, but they wrote f to
make it confusing.

Number of USD equivalent to French francs are given above. 1 Franc equals 1/5 USD.
So x Francs or for this case  f  equals f/5 francs.

JeffTargetTestPrep · Answer

We are given that 175 billion French francs = 35 billion United States dollars. We need to convert f francs to dollars. We can let x be the number of dollar that is equivalent to f francs and solve this problem using a proportion.

(175 billion)/(35 billion) = f/x

175/35 = f/x

175x = 35f

x = 35f/175

x = f/5

Answer: D

PareshGmat · Answer

Drop the term "Billion"

175f = 35d

f = \frac{35}{175} * d

f = \frac{1}{5} * d

Answer = D

Parco · Answer

You know that 175 Francs are equal to 35 USD. (Because both currencies are in billions anyway, you can ignore the units here)

The question asks for the right-hand side of the expression USD=.... and tries to confuse you by giving you variable "f" to represent the number of Francs. Don't let the GMAT trick you, you know better than that. You probably recognized that there is a variable in every answer choice. Get your thoughts straight and pick a smart value for "f". In fact, the question already provided you with a smart number. 175.

--> If Francs= f =175 and USD=35:

Francs(or "f)*x=USD
175*x=35
x=35/175=1/5 --> So f*1/5=USD, or f/5=USD

Success2015 · Answer

we can eliminate few options if we are running out of time
175 francs is equivalent to 35 dollars. ..
so the dollar equivalent of f francs has to be a figure less than f itself. 
eliminate b and c.

Bunuel · Answer

Check other  Conversion problems  to practice in  Special Questions Directory .

Temurkhon · Answer

Just logic:

1 dollar is 5 times as expensive as 1 franc. So if you have F as a amount of francs, the equivalent amount of dollars is F/5

Algebra: 175f=35d => 5f=d, so f=d/5

D

law258 · Answer

175 Francs = 35 Dollars (removed Billion portion for simplicity)

175F=35D (1)
175F/35=D (manipulate (1)) & reduce --> F/5 = D

D.

KrishnakumarKA1 · Answer

175 billion francs = 35 billion dollars
1 franc = 35/175 dollar = ⅕ dollar
 f  francs =  f /5 dollars

dave13 · Answer

Bunuel if 1 USD equals 5 CHF then why option B is icorrect ?

5 USD = 5*5 CHF pushpitkc may be you can explain the logic

the question is : which of the following expressions represents the number of United States dollars equivalent to f francs? Dollar to Franc 1 dollar = 5 francs so 1d = 5F so why B option is incorrect ?

Hero8888 · Answer

The easiest method from my school time:

175 = 35
f = x (x - what we need to find),

multiply by diagonal numbers that do not have x and divide it then by the number, which is diagonal to x

x =F*35/175

It's a very convinient method to convert numbers.

Bunuel · Answer

The question asks: which of the following expressions represents the number of United States dollars equivalent to  f  francs?

So, the question is:  f francs = ? dollars . Do you see the difference between the actual question and the answer you are getting (highlighted)?

1 dollar = 5 francs, so 1 franc = 1/5 dollars. Therefore, f francs = f/5 dollars.

LeoN88 · Answer

175 = 35
1= 35/175
Then f = (35/175) * f => f/5

BrentGMATPrepNow · Answer

We can solve this question using  equivalent ratios  in the form:  French francs / United States dollars

Let  x  = United States dollars equivalent to  f  francs

We get:  175 / 35  =  f / x 
Cross multiply to get: 175x = 35f
Divide both sides by 175 to get: x = 35f/175
Simplify to get: x = f/5

Answer: D

Cheers,
Brent

Pradd1984 · Answer

If 175 billion French francs is equivalent to 35 billion United States dollars, which of the following expressions represents the number of United States dollars equivalent to  f  francs?

A) f-140
B) 5f
C) 7f
D) f/5
E) f/7

Take away the billion so 35 usd = 175 francs or 1 usd = 5 francs.

plugin a number for f franks that equals 1 usd for every 5 francs.
5 francs = how many usd? answer 1
10 francs = 2 usd
15 = 3 usd etc

plugin the chosen number in each answer choice and choose the correct answer. 
so if you choose 10 for f, look for the answer that gives 2. 
D) 10/5 = 2
Answer = D

altairahmad · Answer

Why has this been tagged as a 700 level question ?

Bunuel · Answer

The difficulty level of a question is calculated automatically based on the timer stats from the users which attempted the question.

DanTheGMATMan · Answer

We love to convert. They make up f to be confusing but its just a variable:

https://www.youtube.com/watch?v=OjD8tlSZyLU

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

If 175 billion French francs is equivalent to 35 billion United States

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

If 175 billion French francs is equivalent to 35 billion United States

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards