Bill, Phil and Jenny are siblings. Bill is twice as old as Phil. Jenny is two years younger than Bill. Currently, their dad is twice as old as the sun of their ages. In nine years, their dad's age will be equal to the sum of his three kids' ages at that time. What is Jenny's
current age?

9514 1404 393

  6

Step-by-step explanation:

Let p, b, j, d represent the ages of Phil, Bill, Jenny, and Dad. We are given the relations ...

  b = 2p

  j = b -2

  2(p +b +j) = d

  (p+9) +(b+9) +(j+9) = d+9

Solving the last equation for d, we get ...

  (p +b +j) +18 = d

Substituting for the sum of p, b, j in the third equation, we have ...

  2(d -18) = d

  d = 36 . . . . . . . . add 36-d

Substituting for b and j in the third equation, we get ...

  2(p +(2p) +(2p-2)) = 36 . . . . .  uses b=2p in the 2nd equation

  10p -4 = 36 . . . . . . . . . . . . . . . collect terms

  p = 40/10 = 4 . . . . . . add 4; divide by 10

  b = 2p = 8

  j = b -2 = 6

Jenny's current age is 6.

All of the ages are ...

  Bill: 8; Jenny: 6; Phil: 4; Dad: 36

7. d. 64

8. i. 32

9. c. 125

10. j. none of the above

11. d. 81

12. i. 216

13. e. none of the above

14. g. 240

15. e. none of the above

16. g. 32

17.   e. none of the above

30 miles

step-by-step explanation:

we know that 60 seconds equals 1 minute and 60 minutes 1 hour

44 ft       60 sec     60 min     158400   ft

  *   *   =

1 sec       1 min       1 hour         hour

we know that there are 5280 ft per mile

158400   ft       1 mile         30 miles

  *   =

1   hour               5280 ft     1 hour

so in 1 hour   it can travel 30 miles