Digging -28 would take 16 hours because 14 times 2 equals 28 and 8 times 2 equals 16 so answer is 16
This is a physics problem.
The law is that the momentum is preserved: total momentum before collsion = total momentum after collision
Momentum before collision = 80 kg.m/s - 100 kg.m/s = -20 kg.m/s
Then answer is b. - 20 kg.m/s

Here's the solution ~
The given points are : (-7 , -4) and (1 , 1)
now, let's use distance formula to find the distance between them !





The answer is 96 min, here is why:
x / 240 + x / 160 = 1
<span>2x + 3x = 480 </span>
<span>5x = 480 </span>
<span>x = 96 min
(</span><span>Drainage rate of first pipe = 480000/240 = 2000 l/min </span>
<span>Drainage rate of second tube = 480000/160 = 3000 l/min </span>
<span>Combined drainage rate = 5000 l/min </span>
<span>Time to drain = 480000/5000 = 96 min. )</span>