Its 15 boats bcuz...252+288=540 and 540/36= 15 boats :D
Well the answer is 4 because 13 in the water
9 more than the ones on the log
so the log has 9 turtles less than the turtles in the water
7.8456 x 10^(-4)
this means you move the decimal place to the left 4 places to get the actual value