Evaluate x - 3y when x = -2 and y= -4 A. -10 B. -4C. 4D. 14
2 answers:
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Answer:
a) Cost of flying from A to B = $425
b) Total distance travelled by Piravena during the complete trip = 7,500 km
c) To minimize cost and arrive at the final cost given, she must have travelled by bus from B to C and then travelled by taking an airplane from C to A.
Step-by-step explanation:
The complete question is presented in the attached image to this question.
Full Question
a) To begin her trip she flew from A to B. Determine the cost of flying from A to B.
b) Determine the distance she travels for her complete trip.
c) Piravena chose the least expensive way to travel between cities and her total cost was $1012.50. Given that she flew from A to B, determine her method of transportation from B to C and her method of transportation from C to A.
Solution
a) The distance from A to B is given as 3250 km.
To take an airplane, it costs her a $100 booking fee, plus $0.10 per kilometer.
So, to fly 3250 km, she will pay
100 + (0.10×3250) = $425
b) For her complete journey, she is to make a trip from A to B then from B to C, then from C to A.
Her complete distance travelled = AB + BC + CA
But it is given that the three cities form a right angled triangle as given in the question with AB serving as the hypotenuse side.
Pythagoras theorem gives that the square of the hypotenuse side is equal to the sum of the respective squares of the other two sides
AB² = BC² + CA²
3250² = BC² + 3000²
BC² = 3250² - 3000² = 1,562,500
BC = √1,562,500 = 1,250 km
Total distance covered by Piravena during the entire trip = AB + BC + CA = 3250 + 1250 + 3000 = 7,500 km
c) Her total cost of travel = $1012.50
But she definitely flew from A to B at a cost of $425
This means she spent (1012.50 - 425) on the rest of the journey, that is, $587.5
Note that to travel by bus, it is $0.15 per kilometre and to travel by airplane is $100 + $0.10 per kilometre. Indicating that the airplane saves cost on long distance travels while the bus saves cost on short distance travels.
To confirm this, we calculate the two options (bus or airplane) for each route.
If she travels B to C by bus, cost = 0.15 × 1250 = $187.5
If she travels B to C by airplane, cost = 100 + (0.10×1250) = $225
Hence, the bus obviously minimizes cost here.
If she travels from C to A by bus, cost = 0.15 × 3000 = $450
If she travels from C to A by airplane, cost = 100 + (0.10×3000) = $400
Here, travelling by airplane minimizes the cost.
So, if we confirm now that she travelled from B to C by bus and then from C to A by airplane, total cost = 187.5 + 400 = $587.5
which is the remaining part of her total cost is she minimized expenses!
Hope this Helps!!!
