Here the question: Every ten mins, a cell divides to form two new cells. How many cells are present at the end of twenty mins, if there is sufficient food and water for all the cells to continue living?
The answer is 7 ( stated in the past year exam book) but according to my son, he said the answer should be 4. The reason is you will only get to see the end part after the division. Kindly advice. Thank you.

According to me, 7 is correct answer.
At first there is a cell which provided 2 cells after 10min. then each cell again provides 2 cells after 10 min. so, total 7 cells are there.

answer is 4. cells do not give birth to new cells they divide. after 10 min the first first becomes 2. after another 10 min those two split into two so now you have four

www.ehow.com/how-does_5184786_do-cells-make-new-cells_.html