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)
Let x be the cost of a 2-inch marble.
The cost of a 1-inch marble is x - 30 cents.
Rochelle spends 10 dollars, which is equal to 1000 cents, for her 25 1-inch marbles.
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. Answer: \boxed{70}.