Erin reads an average of 20 books per year. She read 23, 17, 20, and 19 books in four different years. How many books did Erin read in the 5th year to make it an average of exactly 20.0 per year?
17
20
21
19
Mathematics
4.85 M Players
Today is Carl's birthday. In 6 years, he will be 1.25 times older than 4 years ago. How old is he?