Question:
Which of the following are the cubes of odd numbers?
(i) 125
(ii) 343
(iii) 1728
(iv) 4096
(v) 9261
Solution:
The cube of an odd number is an odd number. Therefore, 125, 343 and 9261 are the cubes of odd numbers.
$125=5 \times 5 \times 5=5^{3}$
$343=7 \times 7 \times 7=7^{3}$
$9261=3 \times 3 \times 3 \times 7 \times 7 \times 7=3^{3} \times 7^{3}=21^{3}$