Three phones in a shipment of eighteen are known to be broken. A randomly selected phone is removed from the shipment and tested. It is found to be fine and not broken. If a second phone is randomly selected from those remaining, what is the probability of it NOT being broken?
1/6
1/9
2/17
3/17
14/17

Step-by-step explanation:

Number of phones broken = 3

Number of phones not broken = 15

Total number of phone in the shipment = 18

Since a not broken phone has been randomly selected, the number of phones not broken reduces to 14. And the total number of phones would be 17.

Pr(of newly selected phone NOT broken) =

                                           =

Therefore, the probability of the selected phone not being broken is .

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.