Which part of the neuron sends messages to other neurons?

Axon

An axon is part of neuron with long single fiber that sends messages to the dendrites of other neurons. They transmit information away from the cell body and may have myelin covering to protect the axon and help to fasten the speed of transmission of the signal that deliver the message to other neurons, tissue like the muscles and organs.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.