**Solve this:**

*Data:*

A, B, C, and D want to get across a lake 312 miles across.

Swimming speeds in mph: A=4, B=8, C=12, and D=16!

They have a motorboat that goes at 48mph but this boat can only take 2 persons.

D leaves first; 2 hours later the other 3 leave.

During the last hour, a strong salmon decides to push the boat. This causes the boat to go 72mph during the last hour.

All 4 arrive on other side at same time, 16 hours after D left.

*Questions:*

How many miles did the boat travel?

For how many hours did A swim?

How many miles did C swim?

How many hours was B in the boat?

**NOTE:** Everything is in complete miles and hours (no fractions of nothing), all speeds are constant, no interfering currents, no lost of time getting in/out of boat, no loss of time doing boat u-turns, no hanging on to the back of the boat or other such dishonest stuff; in other words, no dirty tricks to make your life miserable.

Are you sure? This action cannot be undone.
Explanation:

D left 1st....

Hour no 1: D-16 miles

Hour no 2: D-32 miles

next A and B leave with the boat while C starts to swim..

Hour no 3: D-48 miles, A-48 miles, B-48 miles, C-12 miles

Hour no 4: D-64 miles, A-96 miles, B-96 miles, C-24 miles

Hour no 5: D-80 miles, A-144 miles, B-144 miles, C-36 miles

Hour no 6: D-96 miles, A-192 miles, B-192 miles, C-48 miles

Hour no 7: D-112 miles, A-240 miles, B-240 miles, C-60 miles

At this moment B leaves the boat, starts swimming and A comes back to take C....

Hour no 8: D-128 miles, A-192 miles, B-248 miles, C-72 miles

Hour no 9: D-144 miles, A-144 miles, B-256 miles, C-84 miles

Hour no 10: D-160 miles, A-96 miles, B-264 miles, C-96 miles

So, A meets C and C joins the boat....

Hour no 11: D-176 miles, A-144 miles, B-272 miles, C-144 miles

Hour no 12: D-192 miles, A-192 miles, B-280 miles, C-192 miles

Hour no 13: D-208 miles, A-240 miles, B-288 miles, C-240 miles

Hour no 14: D-224 miles, A-288 miles, B-296 miles, C-288 miles

C leaves the boat, starts swimming and A comes back to take D....

Hour no 15: D-240 miles, A-240 miles, B-304 miles, C-300 miles

At the last hour, D joins the boat and boat travels with 72 miles/hr,

Hour no 16: D-312 miles, A-312 miles, B-312 miles, C-312 miles.....

All 4 reach at the same time..................

Are you sure? This action cannot be undone.