Ex: solve for x
x+3=7 since I want to get x by itself i remove the three.
x+3-3=7-3 The opposite of plus 3 is minus 3, and whatever I do to one side i MUST do to the other side, so you want to subtract 3 from both sides.
x=4 so, 3 minus 3 = 0 and 7 minus 3 = 4.
Answer:
- c) 62.5 mA
- c) 9 seconds
Step-by-step explanation:
1. resistance is multiplied by 20/5 = 4, so current is multiplied by 1/4.
(1/4)(250 mA) = 62.5 mA . . . . matches choice C
__
2. distance is multiplied by 144/16 = 9, so time is multiplied by √9 = 3. The time it takes to fall 9 times as far is ...
3 × 3 seconds = 9 seconds . . . . matches choice C
Recall the double angle identity:

Then

The answer is D from picture you posted .
The lengths are in the proportion
.. top : middle : bottom = 1 : 3 : 6
The top section is 1/(1 +3 +6) = 1/10 of the overall length, hence 24 ft.