A store display rotates 40 times every half hour. How many times will the display rotate in 4 hours?

A store display rotates 40 times every half hour i. e 30 minutes

Thus, by simple calcultion, we say,

Therefore, the store display rotates 80 times in 1 hour i. e. 60 minutes

Now,

Thus, the strore display will rotate 80*4 = 320 times in 4 hours

therefore, the answer is 320 times in 4 hours