64 is a counter example that proves Jim's conjecture as false.
Step-by-step explanation
The number should be less than 100 and need to be both perfect square and perfect cubes.
![64 = 8*8 = (8)^2](https://img.qammunity.org/2019/formulas/mathematics/college/mq7s37ycycfi2aem3ms8tz0ee69adnygyv.png)
So, 64 is a perfect squared number.
Now,
![64= 4*4*4 =(4)^3](https://img.qammunity.org/2019/formulas/mathematics/college/1vjuy6khaboxgxj2d0hblrbyhmymc6y67f.png)
So, 64 is also a perfect cubed number.