three fireworks are fired at the same time.

The first one is fired every 64 seconds, the second one is fired every 84 seconds and the third one is fired every 96 seconds.
How many seconds after they start will it take until all three fireworks are again fired together?

look at Ms Sue's solution for this question

http://www.jiskha.com/display.cgi?id=1473473272

and then adjust it to yours.

To find the time it takes until all three fireworks are fired together, we need to find the least common multiple (LCM) of the given firing times.

Step 1: Find the prime factors of each firing time:
64 = 2^6
84 = 2^2 * 3 * 7
96 = 2^5 * 3

Step 2: Take the highest exponent for each prime factor among the three firing times:
2^6
3^1
7^1

Step 3: Multiply the highest exponents to find the LCM:
2^6 * 3^1 * 7^1 = 64 * 3 * 7 = 1344

Therefore, it will take 1344 seconds for all three fireworks to be fired together again.