Giant Impact Hypothesis is the theory that says that the moon formed from the dust produced by a collision between Earth and another large body.
Earth was formed from the leftover cloud of dust and gas orbiting around the sun. During the early solar system, large bodies kept on crashing with each other and many bodies were created from dust and gas but never achieved its planetary status.
According to the Giant Impact Hypothesis, one of this incomplete body called Theia crashed into Earth. The vaporized chunks of both Earth and Theia were flung into space and was bound together by gravity, thus creating the Moon.
I think the answer is 80 because if he makes 20 loaves of bread each morning, and 10 more every half an hour for three hours ( 20 + 60 = 80) the answer should be 80. Correct me if I'm wrong please, Thank You!