We have changed the way we log in on College Confidential. Read more here.
Math help center
Arachnotron
1658 replies103 threads Senior Member
Give me any SAT Reasoning Test math question (or a question from a simulated practice test) and I'll post a solution. Specify detail (just the math work or explicit reasoning or w/e) if you want. I'll post ridiculously detailed solutions by default.
312 repliesPost edited by Arachnotron on
This discussion has been closed.
Replies to: Math help center
#5 pg. 472 of Blue Book
#6 pg. 472 of BB
#8 pg. 473 of BB
1. http://img16.imageshack.us/img16/3329/q34g.jpg
2. http://img193.imageshack.us/img193/9058/78224058.jpg
3. http://img195.imageshack.us/img195/6129/52012792.jpg
Thanks.
Image 1:
#15:
Since OD bisects <AOF, you know that m<AOD = m<DOF, and since you know that OC bisects <AOE, that m<AOB + m<BOC = m<COD + m<DOE, and since OB bisects <AOD, you know that m<BOC + m<COD = x = 40
Now since m<BOC + m<COD = 40, and since we know that OD bisects <AOF, we know that
40 + m<BOC + m<COD = 30 + m<DOE. Substituting, it is easy to see that the expression boils down to 40 + 40 = 30 + m<DOE, which gives that m<DOE is 50.
Finally, we want to find <BOE, which we can do by adding m<BOC + m<COD + m<DOE, which from the information we have derived simplifies to 40 + 50 = 90
#17:
Since we remove every 4 inches, it is useful to find out how many triangles we will remove. This can be found by: 80/4 = 20. Then, notice that for every 1 inch you remove, you gain back 2 inches. So we gain back 20(2-1) = 20 inches, which would make our total length 100 .
#20
You know that the total rope length will be y + 4x, so the insight needed is an expression of y in terms of x. Luckily, we have area which gives xy = 4000. Now, rearranging, we see that x = 4000/y, which we can substitute into our expression to yield 16000/y, choice B
#7
Sum of the arc measures is 2pi or 360 degrees. It's divided into 5 equal segments. ABC gets two of these segments, which leaves 3 of these segments to AEC. Thus ratio of ABC to AEC is 2:3, choice B .
Tom's rate: 100 ft/27 sec
Bill's rate: 90 ft/27 sec.
(27sec/90ft)(100ft) = 30 seconds.
filling entries of an initially empty 2008
The answer is Barbara.
Take a look at it this way: whenever Alan puts some number, n, in an entry in some row, Barbara can just write its negative in the same row. If you continue this process -- since there are an even number of spots -- all the rows will add up to zero so you end up with a matrix that is rank deficient, thus proving Barbara has a winning strategy.
If four men need $24 worth of food for a three-day camping trip, how much will two men need for a two-week trip?
I got $56
If it takes 16 faucets 10 hours to fill 8 tubs, how long will it take 12 faucets to fill 9 tubs?
I got 15 hours
Are these solutions correct?
#1:
Correct.
#2:
16 faucets 10 hours to fill 8 tubs can be reduced to 2 faucets 10 hours hours to fill 1 tub
So, it would take 10/6 hours for 12 faucets to fill 1 tub, and then (5/3)(9) to fill 9 tubs, which gives you the correct answer of 15.