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Difficult Math Problem #108 - Probability
A and B alternately toss a coin. The first one to turn up a head wins. if no more than five tosses each are allowed for a single game. 1- Find the probability that the person who tosses first will win the game? 2- What are the odds against A's losing if she goes first? oa coming when people respond...
- by 800guy
Mon Mar 12, 2007 12:02 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #108 - Probability
- Replies: 3
- Views: 3575
oa
oa:
don't really understand the oa provided in the doc, but here it is..
$15 gives 14
After that it is an AP with d=2, a=14 and n =99
- by 800guy
Mon Mar 12, 2007 12:01 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #107 - Algebra
- Replies: 7
- Views: 2590
Difficult Math Problem #107 - Algebra
If operation $ is defined as
$X = X + 2 if X is even
$X = X - 1 if X is odd,
what is $(...$($($(15)))...) 99 times?
(A) 120
(B) 180
(C) 210
(D) 225
(E) 250
from diff math doc, oa coming when people reply with explanations
- by 800guy
Fri Mar 09, 2007 10:49 am- Forum: Problem Solving
- Topic: Difficult Math Problem #107 - Algebra
- Replies: 7
- Views: 2590
- by 800guy
Fri Mar 09, 2007 10:49 am- Forum: Problem Solving
- Topic: Difficult Math Problem #106 - Combinations
- Replies: 11
- Views: 8574
Difficult Math Problem #106 - Combinations
If 10 persons meet at a reunion and each person shakes hands exactly once with each of the others, what is the total number of handshakes?
(A) 10!
(B) 10*10
(C) 10*9
(D) 45
(E) 36
oa coming after some ppl answer with explanations. from diff math doc.
- by 800guy
Wed Mar 07, 2007 10:10 am- Forum: Problem Solving
- Topic: Difficult Math Problem #106 - Combinations
- Replies: 11
- Views: 8574
- by 800guy
Wed Mar 07, 2007 10:09 am- Forum: Problem Solving
- Topic: Difficult Math Problem #105 - Mixtures
- Replies: 9
- Views: 2325
Difficult Math Problem #105 - Mixtures
Four cups of milk are to be poured into a 2-cup bottle and a 4-cup bottle. If each bottle is to be filled to the same fraction of its capacity, how many cups of milk should be poured into the 4-cup bottle? A. 2/3 B. 7/3 C.5/2 D. 8/3 E. 3 from diff math doc, oa coming when some people answer with ex...
- by 800guy
Mon Mar 05, 2007 12:19 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #105 - Mixtures
- Replies: 9
- Views: 2325
oa
oa:
Let x be the number of days that need to be worked
500x - 1500 > 400x - 550
100x > 950
x > 9.5 (D)
- by 800guy
Mon Mar 05, 2007 12:18 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #104 - Work
- Replies: 4
- Views: 3191
Difficult Math Problem #104 - Work
from diff math doc. oa coming when some people answer with explanations: Machine A can produce 50 components a day while machine B only 40. The monthly maintenance cost for machine A is $1500 while that for machine B is $550. If each component generates an income of $10 what is the least number of d...
- by 800guy
Fri Mar 02, 2007 10:24 am- Forum: Problem Solving
- Topic: Difficult Math Problem #104 - Work
- Replies: 4
- Views: 3191
oa
here's the OA:
total = gr1 + gr2 - both + neither
20 = 8 + P - 7 + 10
P = 9, 9 students study both P and M, 7 study both, 9-7 = 2 study only P
- by 800guy
Fri Mar 02, 2007 10:23 am- Forum: Problem Solving
- Topic: Difficult Math Problem #103 - Sets
- Replies: 7
- Views: 3475
Difficult Math Problem #103 - Sets
Out of 20 surveyed students 8 study math and 7
study both math and physics. If 10 students do not
study either of these subjects, how many students
study physics but not math?
(A) 1
(B) 2
(C) 4
(D) 5
(E) 6
from diff math doc. answer coming when some people respond with explanations
- by 800guy
Wed Feb 28, 2007 7:16 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #103 - Sets
- Replies: 7
- Views: 3475
oa
oa from diff math doc: Jane gave Karen a 5 m head start means Karen was 5 m ahead of Jane. So after the lead, Karen ran 95m and Jane ran 99.75 m when the race ended. Let speed of Karen and Jane be K and J respectively and lets say after X minutes Jane overtakes Karen. 1st condition: 95/K = 99.75/J 2...
- by 800guy
Wed Feb 28, 2007 7:15 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #102 - Rate
- Replies: 4
- Views: 3118
Difficult Math Problem #102 - Rate
Jane gave Karen a 5 meter head start in a 100 meter race and Jane was beaten by 0.25 meters. In how many meters more would Jane have overtaken Karen?
oa coming after some people answered with explanations. from diff math doc.
- by 800guy
Mon Feb 26, 2007 12:42 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #102 - Rate
- Replies: 4
- Views: 3118
oa
oa from the doc: Together they do 1/20+1/12=4/30 of the task. Jane and John started the work together, but only John finished the work because Jane gets sick. So let x be the number of days they worked together. x*3/40+4*1/20=1 x4/30=4/5 and therefore x =6 So in total they worked 6 days on it togeth...
- by 800guy
Mon Feb 26, 2007 12:41 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #101 - Work
- Replies: 8
- Views: 6197
Difficult Math Problem #101 - Work
John can complete a given task in 20 days. Jane will take only 12 days to complete the same task. John and Jane set out to complete the task by beginning to work together. However, Jane was indisposed 4 days before the work got over. In how many days did the work get over from the time John and Jan...
- by 800guy
Fri Feb 23, 2007 3:54 pm- Forum: Problem Solving
- Topic: Difficult Math Problem #101 - Work
- Replies: 8
- Views: 6197