Respuesta :
Represent the speed of the first plane by f and that of the second plane by s.
Then 4f+4s = 3800 miles, or f+s = 950 miles. Thus, f + (f + 80) = 950, so that
2f = 870, and f = 435 mph. Then s = (435+80)mph, or 515 mph.
The first plane flew at 435 mph and the second at 515 mph.
Check: (4 hours)(435 mph) + (4 hours)(515 mph) = 3800 mi (as expected)
Then 4f+4s = 3800 miles, or f+s = 950 miles. Thus, f + (f + 80) = 950, so that
2f = 870, and f = 435 mph. Then s = (435+80)mph, or 515 mph.
The first plane flew at 435 mph and the second at 515 mph.
Check: (4 hours)(435 mph) + (4 hours)(515 mph) = 3800 mi (as expected)
Answer:
The first plane flew at 435 mph and the second at 515 mph.
Step-by-step explanation: