The number that produces an irrational number when multiplied by 0.4 is 3π. The correct option is A. 
To determine which number produces an irrational number when multiplied by 0.4
First and foremost, 0.4 is a rational number.
A rational number is a number that is of the form
where p and q are integers and q is not equal to 0.
0.4 can be written as
or
, hence, it is a rational number.
Now,
Any irrational number when multiplied by a rational number other than zero will also be irrational.
Therefore, we are to determine which of the given options is an irrational number.
π is an irrational number, therefore 3π is also an irrational number
0.444... can be expressed as 4/9, therefore it is a rational number
- For option C.

= 3, which can be expressed as 3/1, therefore it is a rational number
- For option D.

is a rational number
The only irrational number among the given options is 3π
Hence, the number that produces an irrational number when multiplied by 0.4 is 3π. The correct option is A. 
Learn more here: brainly.com/question/11763957
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
a) Hawaii's elevation (1 ft) is greater than both the sea level and California's elevation so it is located near the top. Sea level (0 ft) is less than Hawaii's elevation (1 ft) but more than California's elevation (-120 ft). California's elevation is negative, meaning it is below sea level.
b) California's elevation < sea level < Hawaii's elevation
-120 ft < 0 ft < 1 ft
Answer:
f < 4
Step-by-step explanation:
3f + 9 < 21
21 - 9 = 12
12 / 3 = 4