pike

P. 400 #19
At a bottling company, machine A fills a bottle with spring water and machine B accepts the bottle only if the number of fluid ounces is between 11 7/8 and 12 1/8. If machine B accepts a obttle containing n fluid ounces, which of the following describes all possible values of n?

(A) |n-12|=1/8
(B) |n+12|=1/8
(C) |n-12|<1/8
(D) |n+12|<1/8
(E) |n-12|>1/8

P. 464 #19
Includes figure, so if you have the book please help.

Lakshya M

Pg 400 #19
In this problem clearly 12 ounces is a possible value of n. If you put 12 as n in any of the answer choices except C then you'll get a false equation. Thus C is your answer.

Alternative Method:
We know that 11 7/8 < n < 12 1/8. Subtract 12 from all terms it becomes -1/8< n-12 <1/8, which is |n-12| < 1/8.

Pg. 464 #19
Circumference = 2(pi)r. Length of an arc which subtends angle 'a' at the centre is a/360 x 2(pi)r, in our case a = 30 and the arc length is 6(pi), therefore we can find r. Once we have r we can find the area of the cirlce and divide it by 12 to get the area of the sector. The answer is (A) 108(pi).

pike

Thanks. I have another question: p. 490 #12. It has a figure too.

skywalker99

pike...
p.490#12
Join PR
we r told dat P and Q are syymetric about AB and Q and R are symmetrical about CD.
Lets call the point where PR meets the rectangle(reight between C and D) S.
Therefore PQ=SR
we know QS=4 because BC =4.
Therefore PQ=SR=2 and PR=PQ+QS+SR=4+2+2=8.