I think your talking about refraction and if so the first medium it existed in before entering the second usually has the higher speed especially it the first medium is less denser than the second
The easiest way to explain it is roughly identical to the way that your teacher explained it in class. If there were any easier way ... like writing it here in a few paragraphs ... then that's what the teacher would have done. You would have been given the easy explanation on the first day of class, printed on one sheet of paper, and you would have had the rest of the year to practice it and get really good at it.
If the class spent a month teaching it, then that's about how long it takes. Sorry.
Answer:
(a) F = 320
(b) = F = -5.1625
Explanation:
The formula that converts degree Celsius (C) to degree Fahrenheit (F) is:
F = 1.8C + 32
Solving (a): F = 2C
Substitute 2C for F in the above equation
F = 1.8C + 32
2C = 1.8C + 32
Collect like terms
2C - 1.8C = 32
0.2C = 32
Multiply both sides by 5
5 * 0.2C = 32 * 5
C = 160
Recall that F = 2C
F = 2 * 160
F = 320
Solving (b): F = ¼C
Substitute ¼C for F in the above formula
F = 1.8C + 32
¼C = 1.8C + 32
Convert fraction to decimal
0.25C = 1.8C + 32
Collect like terms
0.25C - 1.8C = 32
-1.55C = 32
Divide both sides by -1.55
C = 32/(-1.55)
C = -32/1.55
C = -20.65
Recall that: F = ¼C
F = -¼ * 20.65
F = -5.1625