If baseball were played on Mars, the balls would fly much farther than they do on Earth. One could then speculate that the number of home runs hit would be much greater on Mars. Mike expects that he would hit 50% more home runs if he were playing baseball on Mars. If he hit 76 homers on Earth, how many home runs does he expect he would hit on Mars?
If Mike thinks he will hit 50% more, this means he will hit the same number of homers he hit on Earth (76) plus half (50%) of that same number. The total number could be represented as one and a half of 76 or 150% of 76.
You can find what number is half of 76 and then add this to 76 to find Mike's predicted number of home runs on Mars.