These items are often used to set up targets for throwing activities, hence target practice. While they could potentially be incorporated into balancing or jumping activities, their primary use is for target practice. They are not typically used in relay races.
Assertion (A): The sum of the first fifteen terms of the AP $ 21, 18, 15, 12, \dots $ is zero.
Reason (R): The sum of the first $ n $ terms of an AP with first term $ a $ and common difference $ d $ is given by: $ S_n = \frac{n}{2} \left[ a + (n - 1) d \right]. $