Marbles come in 2 sizes: 1-inch diameter and 2-inch diameter. The one-inch diameter marbles cost 30 cents less than the two-inch marbles. Rochelle buys 25 one-inch marbles for her science project and spends exactly $10. Find the cost of a two-inch marble.
To find the cost of a two-inch marble, let's set up an equation based on the given information:
Let's assume the cost of a two-inch marble is "x" dollars.
Since the one-inch marbles cost 30 cents less, the cost of a one-inch marble would be "x - 0.30" dollars.
Now, we know that Rochelle bought 25 one-inch marbles for $10. So we can set up another equation using this information:
25(x - 0.30) = 10
Let's solve this equation to find the value of "x."
25x - 7.50 = 10
Adding 7.50 to both sides of the equation:
25x = 17.50
To isolate "x," we divide both sides of the equation by 25:
x = 17.50 / 25
Simplifying:
x = 0.70
So, the cost of a two-inch marble is $0.70.
Let's represent the cost of a two-inch marble as "x" in cents.
According to the given information, the one-inch marbles cost 30 cents less than the two-inch marbles. Therefore, the cost of a one-inch marble would be (x - 30) cents.
Rochelle buys 25 one-inch marbles for her science project and spends exactly $10. Since 1 dollar is equal to 100 cents, Rochelle spends 10 dollars * 100 cents = 1000 cents.
The cost of 25 one-inch marbles would be 25 * (x - 30) cents.
So, we can write the equation: 25 * (x - 30) = 1000
Now, let's solve the equation to find the value of x:
25x - 750 = 1000
25x = 1000 + 750
25x = 1750
x = 1750 / 25
x = 70
Therefore, the cost of a two-inch marble is 70 cents.
Let's assume that the cost of a two-inch marble is $x
The cost of a one-inch marble is $x-30 cents.
Since Rochelle bought 25 one-inch marbles, she spent 25*(x-30) cents which is equal to $10.
So 25*(x-30)=10*100 cents
25x-750=1000
25x=1000+750
25x=1750
x=1750/25
x=$<<70=70>>70
The cost of a two-inch marble is $70. Answer: \boxed{70}.