There are four mobile phones in in house at 5: 00 a. m. all the for mobiles phone will ring together thereafter the first onerings very 15 minutes the second one rings every 20 minutes that one rings every 25 minutes fourth one rings every 30 minutes at what time will the for mobile phones ring together again

after 300 min that mean at they will ring at 10:00 a.m

Step-by-step explanation:

1.phone will ring after 15,30,45,60,75,90,105,120,135,150,165,180,195,210,225,240,255,270,285,300

2.phone will ring after 20,40,60,80,100,120,140,160,180,200,220,240,260,280,300

3.phone will ring after 25,50,75,100,125,150,175,200,225,250,275,300

4.phone will ring after 30,60,90,120,150,180,210,240,270,300

c is the final answer! : )