Question

55 cows can graze a field in 16 days.
How many cows will graze the same field in 10 days?

Answer 1

Let number of cows required = x
Therefore:
$\begin{array}{ccc}\text{Cows}& 55& x\\ \text{Period (in days)}& 16& 10\end{array}$
Less days, more cows
$\therefore$ By inverse variation:
$55:x=10:16\Rightarrow \frac{55}{x}=\frac{10}{16}\Rightarrow 10x=16\times 55\Rightarrow x=\frac{16\times 55}{10}=88$
$\therefore$ Number of cows = 88