Marbles come in two sizes one inch diameter and 2 inch diameter the 1-in diameter marbles cost $0.30 less than the 2 in marbles Rochelle buys 25 1 in marbles for her science project and spends exactly $10 find the cost of a 2 in marble
Let x be the cost of a 2-inch marble.
The cost of a 1-inch marble is x - $0.30.
Rochelle spent $10 on 25 1-inch marbles, so the cost of each 1-inch marble is $10/25 = $0.40.
Thus, x - $0.30 = $0.40.
Therefore, x = $0.40 + $0.30 = $<<0.40+0.30=0.70>>0.70.
The cost of a 2-inch marble is $0.70. Answer: \boxed{0.70}.