Five boxes together have 725 marbles. If the first box has 20marbles more than the other Four. How many marbles are there in the first box
Let's call the number of marbles in the first box "x".
Since the other four boxes have 20 less marbles than the first box, we can represent the number of marbles in each of those boxes as "x - 20".
We know that the total number of marbles in all five boxes is 725, so we can write an equation:
x + (x - 20) + (x - 20) + (x - 20) + (x - 20) = 725
Simplifying this equation, we get:
5x - 80 = 725
Adding 80 to both sides, we get:
5x = 805
Dividing both sides by 5, we get:
x = 161
Therefore, there are 161 marbles in the first box.