Question

A farmer divides his herd of $‘n^{\prime }$ cows among his four sons so that the first son gets one-half the herd, the second son gets one-fourth, the third son gets one-fifth, and the fourth son gets $7$ cows, then $‘n^{\prime }$ is:

• A. $140$
• B. $280$
• C. $180$
• D. $240$

Answer 1

The correct option is A $140$

There are $‘n^{\prime }$ cows :
First son got $n/2$.
Second son got $n/4$.
Third son got $n/5$.
Fourth son got $7$.
Therefore, the sum of cows each son gets is equal to the total number of cows.
$\frac{n}{2}+\frac{n}{4}+\frac{n}{5}+7=n$
$\therefore n=140$