Final answer:
Jerry used 2 lives to beat the 1st world, determined by dividing the 10 lives used for the 2nd world by 5.
Step-by-step explanation:
Jerry used 10 lives to beat the 2nd world and it took him 5 times as many lives as it did to beat the 1st world. To find out how many lives it took him to beat the 1st world, we need to divide the number of lives used for the 2nd world by 5.
Let x represent the number of lives Jerry used to beat the 1st world. The equation based on the given information is:
5 * x = 10
Now, we solve for x:
x = 10 / 5
x = 2 lives
Therefore, Jerry used 2 lives to beat the 1st world.