Question

When a crab hatches from an egg, it shell is 1cm across, when fully grown its shell in 10cm. Each new shell grows one third bigger than the previous one. How many shells does a fully grown crab have during its life.???

Answer 1

Question seems incomplete check it

Answer 2

by the way if its complete then you only need to solve Arithmetic Progression

Answer 3

This can be modeled by the following equation:\[10=(1+\frac{1}{3})^{n}\]
where n is the number of shells needed to reach 10 cm.
You need to solve the equation to find n.
Hint: Take logs of both sides of the equation.