Answer :
The ratios add up to 10 so 42/10 is 4.2 and as b is 3parts you times 4.2 by 3 giving you 12.6
Answer: The correct option is (B) 12.6.
Step-by-step explanation: Given that an industrial cleaner is manufactured using only the 3 secret ingredients A, B, and C, which are mixed in the ratio of 2 : 3 : 5 respectively, by weight.
We are to find the number of pounds of the secret ingredient B that are in a 42-pound bucket of this cleaner.
Let the quantities of the ingredients A, B and C in the cleaner be 2x, 3x and 5x respectively.
Then, according to the given information, we have
[tex]2x+3x+5x=42\\\\\Rightarrow 10x=42\\\\\Rightarrow x=\dfrac{42}{10}\\\\\Rightarrow x=4.2.[/tex]
Therefore, the quantity of the ingredient B is given by
[tex]3\times4.2=12.6~\textup{pounds}.[/tex]
Thus, option (B) is CORRECT.