Answer:
$23.52
Step-by-step explanation:
So first you would have to find how much each one would be if you were buying one individual book. For that you would do 31.36/4 to get $7.84. Then since you found that for only 1 book, you would need to multiply that by 3 to get $23.52
0.5% or 1/2% of say "x" is 250, whilst "x" is the 100%.
![\begin{array}{ccll} \%&amount\\ \cline{1-2} \frac{1}{2}&250\\[1em] 100&x \end{array}\implies \cfrac{~~ \frac{1}{2}~~}{100}=\cfrac{250}{x}\implies \cfrac{1}{200}=\cfrac{250}{x}\implies x = 50000](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Bccll%7D%20%5C%25%26amount%5C%5C%20%5Ccline%7B1-2%7D%20%5Cfrac%7B1%7D%7B2%7D%26250%5C%5C%5B1em%5D%20100%26x%20%5Cend%7Barray%7D%5Cimplies%20%5Ccfrac%7B~~%20%5Cfrac%7B1%7D%7B2%7D~~%7D%7B100%7D%3D%5Ccfrac%7B250%7D%7Bx%7D%5Cimplies%20%5Ccfrac%7B1%7D%7B200%7D%3D%5Ccfrac%7B250%7D%7Bx%7D%5Cimplies%20x%20%3D%2050000)
Try this solution:
Answer: 6 & 4.5 (m-per-h)
Step-by-step explanation:
- The basic formula used in this task is S=V*t, where S - distance, V - speed, t - time.
- the downstream speed is: V+Vc, where V - the speed of the boat in still water, Vc - the speed of the current.
- the upstream speed is: V-Vc.
- according to the described above the distance for downstream is S1=(V+Vc)*t1, where t1=10; the distance for upstream is S2=(V-Vc)*t2, where t2=70.
- for whole travel down- and upstream: S=S1+S2.
- Using these it is possible to make up the system of the equations:

V - the speed of the boat in still water - 6 miles per hour, Vc - the speed of the current - 4.5 miles per hour. All the details for the system of the equations are in the attachment.
Answer:
3/2 3*5=15
3/2=1.5
Step-by-step explanation:
The blanks are as follows:
- Angle addition postulate
- Subtraction property of equality
- Corresponding sides of similar triangles are proportional
- Multiplication property of equality