CPhill

18 / .25  =    72   glasses

4.A rectangular room is 3 times as long as it is wide, and its perimeter is 48 meters. Find the dimensions of the room. 

Note           3W  =   L

So

48  = 2 ( W + L)

48  =2  (  W +  3W)

48  = 2 (4W)

48   =  8W

W  =48/8 =    6  m

L = 3W  =  3 (6)  =  18 m

3.You are choosing between two different cell phone plans. The first plan charges a rate of 22 cents per minute. The second plan charges a monthly fee of $39.95 plus 9 cents per minute. 
Let t be the number of minutes you talk C 1 and C 2 be the costs (in dollars) of the first and second plans. Find the number of talk minutes that would produce the same cost for both plans 

NOTE: Round to two decimal places for your final answer.

If you talk for________________ minutes the two plans will have the same cost.

3995 + 9t  = 22M

3995   =  22t  - 9M

3995 =  13t

t  =3995/13    ≈   307.3  minutes will  equalize the  cost

2.The perimeter of a rectangle is 78 cm. If the length is 28 cm, how wide is the rectangle?
Find the width of the rectangle.

Perimeter = 2 (W + L)

78  = 2 ( W  + 28)    divide  both sides  by  2

39  =  W +  28

39  - 28 = W   = 11

1.    13.35 + .18 (151)     = $40.53

A  fills     1/36 of the tank in one minute

B fills     1/48   of the tank in one  minute

After 24 minutes   tank A  been opened the whole time and  had filled    (1/36) * 24  =   24/36 = 2/3   of the tank

So   in   x minutes, tank B  must  have filled  the other 1/3 of the tank

So

(1/48) x  = 1/3             mutiply both sides  by 48

x  = 48/ 3 =   16  minutes

2.You are choosing between two different cell phone plans. The first plan charges a rate of 19 cents per minute. The second plan charges a monthly fee of $39.95 plus 8 cents per minute. How many minutes would you have to use in a month in order for the second plan to be preferable? 

Let M  be the number of minutes we are  looking for

We will express  everything in  cents

If the second plan is  prefereable, it  must be  cheaper than the  first....so.....we have his inequality

3995 + 8M  <   19M

3995  <   19M - 8M

3995 <  11M

3995/11   <  M

363.18 <  M

At about    364 minutes,  the  second plan is cheaper

1.Translate the following verbal statement into an algebraic equation and then solve:
The sum of two times a number and five is eight more than the number.

2N +  5  =  N + 8

2N - N   =   8   - 5

N   =  3

3  2/3   =   11/3

12 *   11/3   =      11  * 12/3   =   ????

2 1/2  =  2.5

10  * 2.5  =   ????