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Source: — Problem Solving |

by Neo2000 » Sat Sep 29, 2007 12:05 am
One Last Question


And thanks :-)
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by wongee » Sat Sep 29, 2007 1:11 pm
Bath tub qtn:

I took it as

Cold Hot
c hrs < hrs OR substitute as,
3 hrs < 5hrs

Therefore, in one hr, the hot and cold water fill, 1/3+1/5=8/15
So, Remaining will be filled in 7/8hrs = 52.5 mins

So total time= one hr + remaining
1+52.5

Now u compare this to each of the answer choices, II will not hold true.

Geometry qtn:

PLease have this confrimed, but in my opinion is the angles of a triangle are equal then the triangles are SIMILAR to each other which means they are proportionate to each other. The qtn says that the area of one if half the other, therefore instead of solving anything u can assume,S=2s
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by wongee » Sat Sep 29, 2007 1:18 pm
Number line:

Note, since it says that they are broken by 7th and 5th, use 35 as the length of the segment. When you draw it out ull see that if broken in five parts the markings are at

0 7 14 21 28 35 For fiths
0 5 10 15 20 25 30 35

Now, compare each of the row II nos. to the ones on the top for the least differentce, You will see that 14 on the top row and 15 on the bottom row = 1

Therefore, 1/35.

Hope this helps! Good luck on your test tomorrow, you'll do great! :-)
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by ldoolitt » Wed Oct 03, 2007 6:40 am
wongee wrote: Geometry qtn:

PLease have this confrimed, but in my opinion is the angles of a triangle are equal then the triangles are SIMILAR to each other which means they are proportionate to each other. The qtn says that the area of one if half the other, therefore instead of solving anything u can assume,S=2s
Not quite correct.

Let a = area of small triangle and A=area of big triangle
h = height of small triangle and H = height of big triangle

2a = A
2*(1/2)*s*h = (1/2)*S*H
2*s*h = S*H
S=2*s*(h/H)

but any two ratios are the same (prove if you want) so
h/H = s/S

S=2*s*(s/S)
S^2=2*s^2
S=root(2)*s
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by ldoolitt » Wed Oct 03, 2007 7:07 am
For 9

L: y=a1*x+b1
K: y=a2*x+b2

y-intercept
L:y=b1
K:y=b2

x-intercept
L:x=-b1/a1
K:x=-b2/a2

Question
is a1*a2>0

1) Insufficient. This gives us b1*b2>0, which does not indicate anything about a1*a2

2) Insufficient. This gives us b1*b2/a1*a2<0. In this case, either the product of b1*b2 could be negative, or the product of a1*a2 could be negative

3) Sufficient. Since the problem with (2) is that you do not know which product is negative, and (1) gives you that the b1*b2 product is positive, then you know that the a1*a2 product must be negative.
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by gabriel » Wed Oct 03, 2007 10:45 pm
ldoolitt wrote:
wongee wrote: Geometry qtn:

PLease have this confrimed, but in my opinion is the angles of a triangle are equal then the triangles are SIMILAR to each other which means they are proportionate to each other. The qtn says that the area of one if half the other, therefore instead of solving anything u can assume,S=2s
Not quite correct....
actually.. absolutely correct, if the angles of the triangle are equal then they are similar to each other ...
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