Answer:120 min
Explanation:
Given
Amanda spent
of her time after school doing Home work
And
of her remaining time riding her bike
It is given that she rode her bike for 45 minutes in a week
Let t be the time after school
therefore Amanda spend
in home work and
time is left
From remaining
time she spends
time riding her bike
therefore 
thus 
therefore time spent on home work is 
You can’t solve it because you don’t have c in the question
Answer:
B = 4.1*10^-3 T = 4.1mT
Explanation:
In order to calculate the strength of the magnetic field, you use the following formula for the magnetic flux trough a surface:
(1)
ФB: magnetic flux trough the circular surface = 6.80*10^-5 T.m^2
S: surface area of the circular plate = π.r^2
r: radius of the circular plate = 8.50cm = 0.085m
B: magnitude of the magnetic field = ?
α: angle between the direction of the magnetic field and the normal to the surface area of the circular plate = 43.0°
You solve the equation (1) for B, and replace the values of the other parameters:

The strength of the magntetic field is 4.1mT
Answer:
a. chemical contamination of streams ans rivers
d. adaptation