Answer: 144 times
Explanation:
In 30 seconds , it beats 36 times
Another 30 seconds - 36 times
Another 30 seconds - 36 times
Another 30 seconds - 36 times
Therefore , in two minutes , it will beat , 36 + 36 + 36 + 36 times
Therefore , it will beat 144 times .
Another Approach
30 Seconds - 36 times
1 second - 36/30 times
Since 120 seconds make 2 minutes , then
120 seconds - 36/ 30 x 120
= 144 times