The traffic lights at three different road crossings change after every 48 seconds, 72 seconds and 108 seconds respectively. If they change simultaneously at
7 a. m., at what time will they change simultaneously again?

please tell step by step​

7 : 7  : 12 am

Step-by-step explanation:

This question pretty much requires us to obtain the lowest number that is common to all three times. The qay to obtain this is by finding the LCM of all three numbers.

This is given as;

48 = 2 × 2 × 2 × 2 × 3

72 =  2 × 2 × 2 × 3 × 3

108 =   2 × 2 × 3 × 3 × 3

The LCM is = 2 × 2 × 2 × 2 × 3 × 3 × 3 = 432 seconds.

Converting to minutes by dividing by 60, the time is = 432 ÷ 60 min = 7 min 12 sec

The next time they would change simultaneously is; 7am + 7 min 12 sec = 7 : 7  : 12 am

correct answer is infinitely many solutions

step-by-step explanation:

2(2x + 3) = -4 + 2(2x + 5)

solving the above equation:

4x + 6 = -4 +4x +10

combining like terms

4x -4x = -4+10-6

0=0

since both sides are 0=0, we end up into true statement it means it has infinite many solutions.

so correct answer is infinitely many solutions

$12. that is my answer.