If it takes one person 4 hours to paint a room and another person 12 hours to
paint the same room, working together they could paint the room even quicker, it
turns out they would paint the room in 3 hours together. This can be reasoned by
the following logic, if the first person paints the room in 4 hours, she paints 14 of
the room each hour. If the second person takes 12 hours to paint the room, he
paints 1 of the room each hour. So together, each hour they paint 1 + 1 of the 12 4 12
room. Using a common denominator of 12 gives: 3 + 1 = 4 = 1. This means 12 12 12 3
each hour, working together they complete 13 of the room. If 13 is completed each hour, it follows that it will take 3 hours to complete the entire room.
This pattern is used to solve teamwork problems. If the first person does a job in A, a second person does a job in B, and together they can do a job in T (total). We can use the team work equation.
Teamwork Equation: A1 + B1 = T1
Often these problems will involve fractions. Rather than thinking of the first frac-
tion as A1 , it may be better to think of it as the reciprocal of A’s time.
World View Note: When the Egyptians, who were the first to work with frac- tions, wrote fractions, they were all unit fractions (numerator of one). They only used these type of fractions for about 2000 years! Some believe that this cumber- some style of using fractions was used for so long out of tradition, others believe the Egyptians had a way of thinking about and working with fractions that has been completely lost in history.
For the answer to the two questions above,
3x + 2y = 36.50 (I)
2x + 5y = 50 (II)
Eliminating x from the two equations by subtraction:
first we multiply equation I by 2 and equation II by 3
6x + 4y = 73
6x + 15y = 150
Subtracting the two,
-11y = -77
y = 7
He earns $7 at the coffee cart
Substituting y into equation I,
3x + 14 = 36.5
x = $7.50
So we can conclude that, he earns a greater wage of $7.50 at the library,
3sqrt(2)
You can either use Pythagorean theorem or special triangle proportions to find the side that is parallel to z. Since in a 45-45-90 degree triangle, the hypotenuse is the leg times the square root of 2, and the hypotenuse is 3, we know that the leg is 3/sqrt(2) which is equal to 3 sqrt(2) / 2. Since z is twice this length, we know that z is equal to 2 x 3sqrt(2)/2 = 3sqrt(2)
Answer:
= 
= 
Step-by-step explanation:
triangle ADE and triangle ABC are similar
therefore, the ratio of their corresponding sides are equal
Answer:
The function 
is represented by 
.
Step-by-step explanation:
Statement indicates that atmospheric pressure decreases exponentially when height above sea level is increased. This fact is represented by the following model:
(Eq. 1)
Where:
- Atmospheric pressure at sea level, measured in kilopascals.
-Atmospheric pressure decrease rate, dimensionless.
- Height above sea level, measured in kilometers.
- Current pressure, measured in kilopascals.
If we know that 
and 
, the function is represented by:
