markpterson

pg 408 number 3 and number 4 (can't draw diagram)

#3

*all numbers that are divisible by both 2 and 6 are also divisible by 4*

which of the following numbers can be used to show that the statement above is FALSE

A) 4
B) 8
C) 12
D) 18
E) 24

racnna

it's D....i don't know no.4 tho- don't have the blue book.

markpterson

yeah i know its D but how do u do it

markpterson

and does anyone know how to go about doing number 7 on page 409?

racnna

first look for the answer choices that are divisible by both 2 and 6...i.e. 12, 18 and 24..among these numbers, 18 is the only one that's not divisible by 4..which means 18 makes the statement false.

birk44

#4.
you know that the diameter of the circle is 8 units since it says that BC and AD are tangent to the circle so the radius is 4 and the area is pi(r)^2 or 16pi

birk44

#7.
i don't know if there's a shorter way to do this, but here's what i did.

let t = number of days

for each day the net profit is [amount collected minus the cost] or (k - k/3), so the amount of days to reach $1000 is that quantity times the number of days. so our equation is

t(k - k/3) = 1000, and solve for t to find the number of days...

t(2k/3) = 1000
t=3000/2k

t=1500/k,

so the answer is D