If s - 8t + 20 = 5s - 7t + 1 = 0, then the value of s + t, to the nearest tenth, is ?

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years

Lucy is a dress maker. she sews \dfrac47 7 4 of a dress in \dfrac34 4 3 hour. lucy sews at a constant rate. at this rate, how many dresses does lucy sew in one hour? include fractions of dresses if applicable

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?