Answer:
21
Step-by-step explanation:
the sum of the express of the summation of the notation
Let a = speed of the plane A, and b = speed of plane B.
(Assume that the net effect of the wind is negligible.)
From the first sentence, the distance between A and B after each travels for 1 hour is a + b miles. From the second sentence, after 45 minutes, or 0.75 hour, the distance between A and B is 200 miles. Plane a has traveled 0.75a, while plane B has traveled 0.75b.
Hence a + b = 0.75a + 0.75b +200
==> 0.25(a + b) = 200.
==> a + b = 800.
Therefore planes A and B are 800 miles apart now.
Answer:
7 seconds
Step-by-step explanation:
Distance of the coin above the water is modeled by the equation
where 
is time taken to cover the distance
Now equating with zero.
So, time taken by the coin to hit the water is 7 seconds.
Answer:
9
Step-by-step explanation:
so if 5.5 is in meter let change it to cm because the question want us to give the answer in cm.
now we multiply 5.5 times 100 which is equal to 550.
next we subtract 550 - 220= 330.
finally, the difference between a teacher and student is 330cm .meaning the teacher's desk is 330 cm longer or taller than the student.
