D is partly constant and partly varies with v when v=40,D=150 and when v=54,D=192.

Question

A. Find the formula connecting D and V
B. Hence find D when V is 73.

Answer 1

A. The formula connecting D and V is in the form D = a + b*v, where a is the constant part and b is the varying part.

Using the given values when v=40, D=150:
150 = a + b*40

Using the given values when v=54, D=192:
192 = a + b*54

Now, we can solve these two equations simultaneously to find the values of a and b:

150 = a + 40b
192 = a + 54b

Subtracting the first equation from the second:
42 = 14b
b = 3

Substitute b=3 into the first equation:
150 = a + 40*3
150 = a + 120
a = 30

Therefore, the formula connecting D and V is D = 30 + 3v.

B. When v=73:
D = 30 + 3*73
D = 30 + 219
D = 249

Therefore, when v is 73, D is 249.