9514 1404 393
Answer:
- s + a = 250
- 3s + 5a = 1050
Step-by-step explanation:
Let s and a represent the numbers of student and adult tickets sold. The system of equations that can be written from the given information is ...
s + a = 250 . . . . . . total of tickets sold
3s +5a = 1050 . . . dollar value of tickets sold
_____
The solution is (s, a) = (100, 150). 100 student tickets and 150 adult tickets were sold.
Join the centre O to the chord (let it be MN) & let OH be the perpendicular to the chord
OH bisects MN into 2 equal parts (each one is x/2)
OMH is a right triangle with one side =8, the second leg =x/2 & the hypotenuse = 12 (Radius)
Apply Pythagoras:
12² = 8² +(x/2)² ==>144=64 + x²/4 ==> x²=4(144-64) =320
x²=320==> x=√320 =17.88 ≈17.9
Current value of the boat = $45000
Rate at which the value decrease = 8.5%
Value decreased after 1 year = 
Hence, value becomes = 
Value decreased after 2nd year =
Hence, value becomes = 
Value decreased after 3 year =
Hence, value becomes = 
So, value of the boat after 3 years becomes $34472.74
Again, nice problem. These are not super easy. You need to imagine the triangles in the figure and relate sides.
For instance: ADC, its hypotenuse is 15
For ABC, it is 20,
so 20/15 is the ratio between both triangles. Now let's choose the side with 'x'
x is one side of ADC, the corresponding side in ABC is 15 (the second longest sides). You need to rotate the triangles, etc ... That's the tricky part :)
So:
20/15 =15/x ----> x = 15*15/20 = 225/20 = 45/4
Which is C
Not sure whether it's too late to help you though!!!!
Also notice that it's kind of a product rule:
x * 20 = 15 * 15
I am sure the book explains a short way of getting to this equation, like sides opposite, blah blah, but what i told you is the reason. You asked for understanding it! Best luck!
