Gmat Prep?? (Alex Ratio)

IMO A
F/J = 3/2
F+40/J=5/3
J=240
What is OA

correct...thanks.

ok i'm confused on this one...

if:

F/J = 3/2
F+40/J=5/3
J=240

I get:

F+40/J=5/3
which reduces to 9+120=10 if I plug in F=3 and J=2 which would be 119 because 129-10 = 119

F/J=3/2
--> 2F= 3J
F= 3J/2

F+40/J = 5/3

--> 3(3J/2 + 40) = 5J ( Substituting value F in terms of J)
9J + 240 = 10J

J= 240

ahhh that makes sense ddm! Thank you!

if you are confused it might be because there were no parenthesis in the above equations that should have been there.

(F+40)/J=5/3

dferm wrote:The ratio of the amount of Alex's fuel oil bill for the month of February to the amount of his fuel oil bill for the month of January was 3/2. If the fuel oil bill for February had been $40 more, the corresponding ratio would have been 5/3. How much was Alex's fuel oil bill for January?

A. $240
B. $300
C. $360
D. $450
E. $540

Please help...

F/J = 3/2 =>2F=3J
(F+40)/J = 5/3
3F+120 = 5J
3*3/2J + 120 = 5J
9J + 240 = 10J
J=240

dferm wrote:The ratio of the amount of Alex's fuel oil bill for the month of February to the amount of his fuel oil bill for the month of January was 3/2. If the fuel oil bill for February had been $40 more, the corresponding ratio would have been 5/3. How much was Alex's fuel oil bill for January?

A. $240
B. $300
C. $360
D. $450
E. $540

We are given that the ratio of the amount of Alex's fuel oil bill for the month of February to the amount of his fuel oil bill for the month of January was 3/2. If F = the amount of the Febuary fuel bill and J = the amount of the January fuel bill, we can create the following ratio:

F : J = 3x : 2x

We are also given that if the fuel bill for February had been $40 more, the ratio would have been 5/3. We can create the following equation to determine x:

(3x + 40)/2x = 5/3

3(3x + 40) = 10x

9x + 120 = 10x

120 = x

Thus, the fuel bill in January was 2x = 2(120) = 240 dollars.

Answer: A