Marbles come in 2 sizes I inch diameter and 2 inch diameter the 1 inch diameter marbles cost 30 cents less than the 2 inch marbles rocky buys 25 1 inch marbles for his science project and spends exactly $10 find the cost of a 2 inch marble? Answer choices 70,10,2.80,2.50
Let's assume that the cost of a 2 inch marble is x cents.
Since the 1 inch diameter marbles cost 30 cents less than the 2 inch marbles, the cost of a 1 inch marble is (x - 30) cents.
Rocky buys 25 1 inch marbles for his science project, so he spends 25 * (x - 30) cents.
We know that he spends exactly $10, which is equal to 1000 cents, so we can set up the equation:
25 * (x - 30) = 1000
Dividing both sides of the equation by 25, we get:
x - 30 = 40
Adding 30 to both sides of the equation, we get:
x = 70
So the cost of a 2 inch marble is $0.70.
Therefore, the correct answer choice is 70.