Question & Answer

If 1m = 3.8 feet, then how many cubic meters will be equal to 700 cubic feet?
A. 12.756
B. 25.93
C. 65.0
D. 213.41

ANSWER Verified Verified
Hint: Proceed the solution of this question using symmetric property then using unitary method and cubing on both sides we can reach our answer.

Complete step-by-step solution -
Given, 1m = 3.8 feet (Here m stands for meter)
In the question it is given that
⇒1m=3.8 ​feet ……. (1)
So using symmetric property (If a = b then b = a)
Hence we can write equation (1) as
⇒3.8feet= 1m
So by using unitary method
$\because $ 3.8feet = 1m
$\because $ 1feet = \[\dfrac{1}{{3.8}}\]m
On taking cube both side
$\because $${\text{1fee}}{{\text{t}}^3} = {\text{ }}{\left( {\dfrac{1}{{3.8}}} \right)^3}{{\text{m}}^3}$ ; Here value of single unit is given
$\therefore $${\text{700 fee}}{{\text{t}}^3} = {\text{ 700}} \times {\left( {\dfrac{1}{{3.8}}} \right)^3}{{\text{m}}^3} = 12.756{\text{ }}{{\text{m}}^3}$; which is the required value of multiple unit.
In other words, we can say that 12.756 cubic meters will be equal to 700 cubic feet.

Note: To solve this particular question, we should have a good grasp on unitary method which is a technique for solving a problem by first finding the value of a single unit, then finding the necessary value by multiplying the single unit value. Overall this method is used to find the value of a unit from the value of a multiple, and hence the value of multiple. Sometimes we might not have given the value of a single unit that we can also find from the value of a multiple. Along with the unitary method we should also have a clear understanding of Symmetric Property of Equality which states that If a = b then b = a. This is one of the equivalence properties of equality.