Why don't you test your equation and see for yourself?
C =5/9[F - 32]. Try 20 degrees C and solve for for F
20 = 5/9F - 17 7/9
20 + 17 7/9 =5/9F
37 7/9 = 5/9F multiply both sides by 9/5
F =37 7/9 x 9/5
F =3,060 / 45 =68 F. Now, if you try 21 C and solve for F, you should get
F =69.8
So, 69.8 - 68 =1.8F. So, for every 1 degree C increase, you get 1.8 F increase.
Now, the reciprocal of that is true as well. In other words, for every 1 F degree increase you get 1/1.8 =5/9 C inrease.
So, the correct answer is "D" on your multiple choice list.
Note: Here is a trick in convering C to F in a very simple way. Suppose you want to convert 15 C to F.
Take 15 x 2 = 30. Then subtract 10% of 30 = 3 from itself. Or: 30 - 3 = 27 and to that you add 32. So:
27 + 32 = 59 F degees EXACTLY!!.
appreciate all answers :)
