Jan 24, 2010
107
0
0
Status
Pre-Dental
A painting which is 4 feet wide and 5 feet
long is surrounded by a rectangular frame
6-inches wide. What percent of the area of
the picture and the frame is occupied by
the frame?
A. 10 1/2
B. 20
C. 30
D. 33 1/3
E. 50​
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The answer is D.

I got B though. The area of the picture is 5 x 4 = 20 ft squared
The area of the picture of the frame is 5 x 5= 25 ft sqaure
Since the frame is 6 inches or half a foot wide I added a half an inch on both sides of the width of the painting, so from 4 the width now became 5. The length of the painting does not change though because adding a rectangualr frame which is 6 inches wide would not affect the length of the painting

Last, I subtracted the area of the pciture and frame from the area of the picture alone and got 5, I then divided this number by 25 and got 20% or choice B.

What did I do wrong?​
 
Jan 24, 2010
107
0
0
Status
Pre-Dental
I see now.. 2 more questions. This time trig

The value of cos (​
π/3) equals the
value of
A. -cos (2
π/3).
B. cos (2
π/3).
C. cos (6
π/3).
D. -cos (5
π/3).
E. cos (4
π/3).

The answer is A
AND:
For all the​
y, the cos y is equal to which of
the following?
A. sin
y

B. cos (​
y + π )
C. sin (-
y)
D. sin
y + cos y

E. cos (-​
y)

I thought the answer to this one is B but it turns out its E.

 

UndergradGuy7

10+ Year Member
Jun 23, 2007
897
2
241
Status
Pre-Dental
I see now.. 2 more questions. This time trig

The value of cos (​
π/3) equals the
value of
A. -cos (2
π/3).
B. cos (2
π/3).
C. cos (6
π/3).
D. -cos (5
π/3).
E. cos (4
π/3).

The answer is A
AND:
For all the​
y, the cos y is equal to which of
the following?
A. sin
y

B. cos (​
y + π )
C. sin (-
y)
D. sin
y + cos y

E. cos (-​
y)

I thought the answer to this one is B but it turns out its E.

Well, I'm not good at trigonometry, but... the unit circle http://www.hsu.edu/uploadedImages/Faculty/lloydm/classes/pt/UnitCircle.GIF

the numbers are given like this (x, y) cos = x, sin =y.
So for cos(pi/3) you can find it on the circle and see it equals 1/2
find cos(2pi/3) and you can find out it equals -1/2 in A it is -cos(2pi/3) so -(-1/2) = 1/2