During the year, an athlete managed to increase the number of miles that they can run from 5 kilometers to 16 kilometers. Find the percentage increase.

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

Mario has $14.35 left in his wallet. he spent $148.43 for tablecloths. then, he spent $92.05 for napkins. how much money did mario have in his wallet to start with?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?