Marbles come into sizes 1 inch diameter and 2 inch diameter 1 inch diameter marbles cost $.30 less than 2 inch marbles. Shel buys 25 1 inch marbles for her science project and spend exactly $10 find the cost of a 2 inch marble.
2.80
0.70
2.50
0.10
Let's assume the cost of a 2-inch diameter marble is x dollars.
According to the information given, the cost of a 1-inch diameter marble is $.30 less than the cost of a 2-inch diameter marble.
So, the cost of a 1-inch diameter marble = x - $.30.
Shel bought 25 1-inch diameter marbles for her science project and spent exactly $10.
25 * (x - $.30) = $10.
25x - $7.50 = $10.
25x = $17.50.
x = $17.50 / 25.
x = $0.70.
Therefore, the cost of a 2-inch marble is $0.70.