Arectangle is formed whose length is twice the width. it is enlarged to a similar rectangle as the width changes at a rate of 4 inches per minute. when the width is 10 inches, how fast is the area of the rectangle changing

Explanation:

Given that,

To find,

Rate of change of area,

Let l is the length and b is the breadth of the rectangle. The area of the rectangle is given by :

Differentiating above equation wrt t

When b = 10 in

So, the area of rectangle is changing at the rate of 160 inches per minute.

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg