Marbles come in two sizes: 1-inch diameter and 2-inch diameter. The 1-inch diameter marbles cost 30 cents less than the 2-inch marbles. Rochelle buys 25 1-inch marbles for her science project and spends exactly $10. Find the cost of a 2-inch marble.(1 point)
Responses
$2.80
$2.80
$0.10
$0.10
$0.70
$0.70
$2.50
Let's assume that the cost of a 2-inch marble is x cents.
Since the 1-inch marbles cost 30 cents less than the 2-inch marbles, the cost of a 1-inch marble would be (x - 30) cents.
Rochelle buys 25 1-inch marbles for her science project, so she spends 25*(x - 30) cents.
We are told that she spends exactly $10, which is equal to 1000 cents.
Therefore, 25*(x - 30) = 1000
Dividing both sides by 25, we get x - 30 = 40
Adding 30 to both sides, we get x = 70
So, the cost of a 2-inch marble is 70 cents.
Therefore, the correct answer is $0.70.