The range is 327 the maxim subtract the minimum
Measure the sides. And when you get all of the sides add them I'll and get the perimeter I think.
Answer: 1.43 hours
Step-by-step explanation:
Let their speeds be = x km/h
The time taken by Tory will be= 50/x hours to dock
Emilio pilots for another 2 hours and this will be= (50/x)+2) hours
Emilio pilots 120 km for (50/x)+2) hours
d/t=r
120/(50/x) +2) =x
120 = [x(50/x) +2)]
120= 50+2x
2x= 120-50
2x = 70
x= 70/2
x = 35
Tory takes 50/35 = 1.43 hours for 50 km.
Try this way:
1. note, that in such tasks mass of <u>pure</u> copper before merging and after merging is the same (this is the base);
2. If the mass of pure copper in alloy with 40% solution is 'x' and the mass of pure copper in alloy with 80% solution is 'y', then It means before merging was x/0.4 and y/0.8, after merging was (x+y)/0.7. It is one equation of the future system.
3. Using 120 kg. of 70% solution, it is possible to define mass of pure copper after merging, 120*0.7(=84 kg.). And before merging it was 'x+y' kg. of pure copper. It is the second equation of the future system.
4. according to the items no.2&3 (to make up the system of two equations and solve it). All the details are in the attached picture.
5. pure copper in 40% solution is 12 kg., pure copper in 80% solution is 72 kg. It means, that the copper alloy with 40% solution is x:0.4=12/0.4=30 kg., and the copper alloy with 80% solution is y:0.8=72/0.8=90 kg.