17-9 = 8
8 is your answer.
Answer:
20
Step-by-step explanation:
40 - 15 = 25
25/1.25=20
Answer:
28 white strands , 20 blue strands and 32 red strands are needed to make a pair of pom-poms
Step-by-step explanation:
Given :A pom-pom manufacturer makes each of its pom-poms with 35% white strands (w), 25% blue strands (b), and 40% red strands (r).
To Find : If each pom-pom has a total of 80 strands, how many of strands of each color are needed to make a pair of pom-poms?
Solution:
Total Strands = 80
White Strands = 35%
No. of white strands = ![35\% \times 80 =\frac{35}{100} \times 80 =28](https://tex.z-dn.net/?f=35%5C%25%20%5Ctimes%2080%20%3D%5Cfrac%7B35%7D%7B100%7D%20%5Ctimes%2080%20%3D28)
Blue Strands = 25%
No. of blue strands = ![25\% \times 80 =\frac{25}{100} \times 80 =20](https://tex.z-dn.net/?f=25%5C%25%20%5Ctimes%2080%20%3D%5Cfrac%7B25%7D%7B100%7D%20%5Ctimes%2080%20%3D20)
Red Strands = 40%
No. of Red strands = ![40\% \times 80 =\frac{40}{100} \times 80 =32](https://tex.z-dn.net/?f=40%5C%25%20%5Ctimes%2080%20%3D%5Cfrac%7B40%7D%7B100%7D%20%5Ctimes%2080%20%3D32)
Hence 28 white strands , 20 blue strands and 32 red strands are needed to make a pair of pom-poms
The span of 3 vectors can have dimension at most 3, so 9 is certainly not correct.
Check whether the 3 vectors are linearly independent. If they are not, then there is some choice of scalars
(not all zero) such that
![c_1 (2,-1,1) + c_2 (3,1,1) + c_3 (1,2,0) = (0,0,0)](https://tex.z-dn.net/?f=c_1%20%282%2C-1%2C1%29%20%2B%20c_2%20%283%2C1%2C1%29%20%2B%20c_3%20%281%2C2%2C0%29%20%3D%20%280%2C0%2C0%29)
which leads to the system of linear equations,
![\begin{cases} 2c_1 + 3c_2 + c_3 = 0 \\ -c_1 + c_2 + 2c_3 = 0 \\ c_1 + c_2 = 0 \end{cases}](https://tex.z-dn.net/?f=%5Cbegin%7Bcases%7D%202c_1%20%2B%203c_2%20%2B%20c_3%20%3D%200%20%5C%5C%20-c_1%20%2B%20c_2%20%2B%202c_3%20%3D%200%20%5C%5C%20c_1%20%2B%20c_2%20%3D%200%20%5Cend%7Bcases%7D)
From the third equation, we have
, and substituting this into the second equation gives
![-c_1 + c_2 + 2c_3 = 2c_2 + 2c_3 = 0 \implies c_2 + c_3 = 0 \implies c_2 = -c_3](https://tex.z-dn.net/?f=-c_1%20%2B%20c_2%20%2B%202c_3%20%3D%202c_2%20%2B%202c_3%20%3D%200%20%5Cimplies%20c_2%20%2B%20c_3%20%3D%200%20%5Cimplies%20c_2%20%3D%20-c_3)
and in turn,
. Substituting these into the first equation gives
![2c_1 + 3c_2 + c_3 = 2c_3 - 3c_3 + c_3 = 0 \implies 0=0](https://tex.z-dn.net/?f=2c_1%20%2B%203c_2%20%2B%20c_3%20%3D%202c_3%20-%203c_3%20%2B%20c_3%20%3D%200%20%5Cimplies%200%3D0)
which tells us that any value of
will work. If
, then
and
. Therefore the 3 vectors are not linearly independent, so their span cannot have dimension 3.
Repeating the calculations above while taking only 2 of the given vectors at a time, we see that they are pairwise linearly independent, so the span of each pair has dimension 2. This means the span of all 3 vectors taken at once must be 2.