Final answer:
Thalia originally bought nine marbles.
Step-by-step explanation:
In this problem, Thalia originally had a certain number of marbles, but lost two of them while playing. She now has seven marbles left. We are asked to find how many marbles she originally bought.
Let's assume that Thalia originally bought x marbles. After losing two marbles, she has x - 2 marbles left. We know that she has seven marbles left, so we can set up the equation x - 2 = 7.
To solve for x, we can add 2 to both sides of the equation: x - 2 + 2 = 7 + 2, which simplifies to x = 9. Therefore, Thalia originally bought nine marbles.
The question asks us to determine how many marbles Thalia originally had before losing two of them. After the loss, Thalia has seven marbles left. Since she divided the original number of marbles evenly between herself and four friends, and now she has seven after losing two, she must have had nine marbles to start with for her share (seven she has left plus the two she lost).
This means Thalia and each of her four friends received nine marbles originally. We can find the total original number of marbles by multiplying the number of people (Thalia and her four friends, which is 5) by the number of marbles each person got (9 marbles). So Thalia must have bought 45 marbles originally (5 people × 9 marbles per person).
Step-by-step explanation:
Determine the number of marbles Thalia has after losing two, which is 7.
Add the two lost marbles to the remaining amount to find out how many marbles Thalia originally had, which is 9.
Since Thalia and her four friends all had an equal number of marbles, calculate the total number of marbles by multiplying the number of people (5) by the marbles per person (9).
The total number of original marbles is 45 (5 × 9 = 45).