Final answer:
Alison's rock collection increased by 40%, which is calculated as 124 rocks (40% of the original 310 rocks). After adding this increase to the original amount, Alison now has a total of 434 rocks.
Step-by-step explanation:
Alison initially had 310 rocks in her rock collection. After three months, her collection increases by 40%. To find out how many rocks she has now, we calculate the increase and add it to the original amount.
To calculate the increase, we multiply the original number of rocks by the percentage increase:
310 rocks × 0.40 = 124 rocks
This is the number of rocks added to Alison's collection. Now, to find the total number of rocks, we add the increase to the original amount:
310 rocks + 124 rocks = 434 rocks
Therefore, Alison now has 434 rocks in her collection.