This one is hard but I hope someone can help me out

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

1. if we have 3 babies what is the probability they’re going to be all boys? 2. if we roll 2 die at the same time what is the probability of getting less than 10 on the first roll and a 5 on the second roll 3. if we have 3 babies what is the probability their is going to be 2 girls? 4. if we have 3 babies what is the probability of having no more than 1 girl? 5. it we have 3 babies and then have another 3 babies what is the probability of us having at least 1 boy and then having all girls?

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. how many hours after the truck's departure will the two meet?