Temperatures in degrees Celsius (C) can be converted to temp

Question

The temperature in degrees Celsius (C) can be converted to temperature in degrees Fahrenheit (F) by the formula  F = \frac{9}{5}*C + 32 . What is the temperature at which F = C?

(A) 20°
(B) (32/5)°
(C) 0°
(D) -20°
(E) -40°

Bunuel · Accepted Answer

SOLUTION

Temperatures in degrees Celsius (C) can be converted to temperatures in degrees Fahrenheit (F) by the formula F = 9/5*C + 32. What is the temperature at which F = C?

(A) 20°
(B) (32/5)°
(C) 0°
(D) -20°
(E) -40°

Substitute F for C and solve:

F = 9/5*F + 32

F = -40°.

Answer: E.

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Abhishek009 · Answer

F = \frac{9}{5}*C + 32

Substitute F = C

C = \frac{9}{5}*C + 32

5C = 9C + 160

Or,  -4C = 160

So,  C = -40

Hence, answer will be (E) -40°

Abdul29 · Answer

By quickly testing out answers, -40 is the only one that equalizes both, (E).

9/5(-40) + 32 = -40, C= -40, when F= -40.

DoItRight · Answer

E. -40

F = 9/5*C + 32
Set both sides equal to each other.
x=(9x/5) + 32
Solve for X
4x/5 = -32
x= -40

susheelh · Answer

Hello Moderators,

I dont know if this was just me, but I read the stem as  F = \frac{9}{5*C}+ 32  and lost some time solving this.

What it actually means is  F = \frac{9}{5}*C + 32 .

Since this is a OG question, do you think this should be made math friendly to be sure someone does not misread it?

Thanks in advance!

Bunuel · Answer

Mathematically 9/5*C can only mean  \frac{9}{5}*C . If it were  \frac{9}{5*C}  it would have been written as 9/(5*C). Still edited.

Kinshook · Answer

Temperatures in degrees Celsius (C) can be converted to temperatures in degrees Fahrenheit (F) by the formula  F = \frac{9}{5}*C + 32 . What is the temperature at which F = C?

F = \frac{9}{5}*F + 32 
 -32= \frac{4}{5}*F 
 -32\frac{5}{4}= F 
 -40= F=C

IMO E

sahuanamika · Answer

F = 9/5*C+32
Here we have two ways:
1. using options and substituting values or 
2.
 We have to find when F=C, so in the equation we can substitute :
 F = 9/5*F +32 
 -4/5*F=32 
 F=-40

Option E

ThatDudeKnows · Answer

In two seconds, we can see that it's not going to be 0. C is out. 
We can also immediately see that we are going to need a negative number. A and B are out.
Eyeballing D: -20 = -180/5 + 32? Nope. D is out.

Answer choice E.

GmatPoint · Answer

If F = C

Then C = 9/5*C + 32
C = (-5/4)*32
C = -40.

Thus, the correct option is E.

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Temperatures in degrees Celsius (C) can be converted to temp

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Temperatures in degrees Celsius (C) can be converted to temp

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