Let
. Then
, and differentiating both sides with respect to
gives
Now, when
, you get
You have
, so
and
. So
Answer:
A. 4 ft 2 in.
Step-by-step explanation:
50/12 = 4.1666667. Round up, so 4.1666667 becomes 4.2.
(35 + 47 + 42 + x) / 4 = 50
(124 + x) / 4 = 50....multiply both sides by 4, cancelling the 4 on the left side.
124 + x = 50 * 4
124 + x = 200
x = 200 - 124
x = 76 <===
The abs were pretty bad and