Question

With the use of three different weights, namely, $1$ gms, $3$ gms, and $9$ gms, how many objects of different weights can be weighed, if the object has to be weighed and the given weights may be placed in either pan of the scale?

• A. $15$
• B. $13$
• C. $11$
• D. $9$
• E. $7$

Answer 1

The correct option is B $13$

Weights used	No. of weighings possible
1. singly	$3$
2. two at a time (Same pan)	$3$
3. Three at a time (Same pan)	$1$
4. two at a time (diff. pans)	$3$
5. three at a time (diff. pans)	$3$
Total	$13$