Question

If $ c = 30 $ and $ d = 8 $ , how do you find the value of $ 2c + 4d $ ?

Answer 1

Hint: We are required to find the value of a function involving two variables for certain given values of the variables. This question requires us to have the knowledge of basic and simple algebraic rules and operations such as substitution, addition, multiplication, subtraction and many more like these. A thorough understanding of functions and its applications can be of great significance.

Complete step-by-step answer:
In the given question, we are required to find the value of function for a certain set of values of variables. The value of a function for a certain set of values of variable is found by substituting the value of variable as specified in the question into the function.
So, we need to replace the variable in the function given to us in the question by the value specified.
So, the function given to us is: $ 2c + 4d $ .
We are required to find the value of $ 2c + 4d $ by replacing the value of variables as $ c = 30 $ and $ d = 8 $ in the function.
Hence, $ 2\left( {30} \right) + 4\left( 8 \right) $
 $ \Rightarrow 2\left( {30} \right) + 4\left( 8 \right) $
 $ \Rightarrow 60 + 32 $
 $ \Rightarrow 92 $
Hence, we get the value of the required expression $ 2c + 4d $ as $ 92 $ by putting in the values of variables c and d as $ 30 $ and $ 8 $ respectively.
So, the correct answer is “92”.

Note: Such questions that require just simple change of variable can be solved easily by keeping in mind the algebraic rules such as substitution and transposition. Substitution of a variable involves putting a certain value in place of the variable. That specified value may be a certain number or even any other variable.