Question

State which of the following are in proportions.

(v) $11:13::4:5$

Answer 1

Checking the proportionality:

If four numbers $x,y,z,w$ are in proportion i.e. $x:y::z:w$, then the product of extremes is equal to the product of means i.e. $xw=yz$.

In the given expression, $x=11,y=13,z=4,w=5$.

Now, $xw=11\times 5=55$ and $yz=13\times 4=52$

Therefore, it can be concluded that $xw\ne yz$.

Final Answer: Hence, the given expression does not represent a proportion.