Answer:
where is the question???..............

Step-by-step explanation:
We start by applying the Pythagorean theorem to the ladder, with its length L as the hypotenuse:

where x is the vertical distance from the top of the ladder to the ground and y is the horizontal distance from the bottom of the ladder to the wall. Taking the derivative of the above expression with respect to time, we get

Solving for dx/dt, we get

We know that

when x = 6 ft. So the rate at which the top of the ladder is going down is


The negative sign means that the distance x is decreasing as y is increasing.
Answer:
h = 9 cm.
Step-by-step explanation:
V = kBh where k is the constant of variation.
From the given info:
32 = k*16*6 = 96k
So k = 32/96 = 1/3.
So we have the equation of variation:
V = 1/3Bh
When V = 60 B = 20, so:
60 = 1/3 20h
20h = 60 * 3 = 180
h = 180 /20 = 9.
Answer:
He can buy 4 model cars
Step-by-step explanation:
∵ His total money = the cost of books + the cost of model cars
∵ He buys 6 books and the price of each book is $2
∵ The cost of each model car is $7 , let the number of model cars is c
∵ He has $40
∴ 6 × 2 + 7 × c = 40
∴12 + 7c = 40
∴ 7c = 40 - 12 = 28
∴ c = 28/7 = 4
∴ He can buy 4 model cars