Marbles come in 2 sizes 1 inch diameter and 2 inch diameter the 1 inch diameter marble 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

Question

0.70
0.10
2.50
2.80

Answer 1

Let the cost of a 2-inch marble be \( x \) (in dollars). Then, the cost of a 1-inch marble would be \( x - 0.30 \).

Rochelle buys 25 1-inch marbles, and we can express the total cost in terms of \( x \):

\[ 25 \cdot (x - 0.30) = 10 \]

Now we can solve for \( x \):

\[ 25(x - 0.30) = 10 \]

Dividing both sides by 25 gives:

\[ x - 0.30 = \frac{10}{25} \]

This simplifies to:

\[ x - 0.30 = 0.40 \]

Adding 0.30 to both sides results in:

\[ x = 0.70 \]

Thus, the cost of a 2-inch marble is $0.70.

So, the answer is:

0.70