In a certain class, the ratio of girls to boys was 5 to 4. if there are 80 boys in the class, how many students are there in all?

At wind speeds above 1000 centimeters per second (cm/sec), significant sand-moving events begin to occur. wind speeds below 1000 cm/sec deposit sand and wind speeds above 1000 cm/sec move sand to new locations. the cyclic nature of wind and moving sand determines the shape and location of large dunes. at a test site, the prevailing direction of the wind did not change noticeably. however, the velocity did change. fifty-nine wind speed readings gave an average velocity of x = 1075 cm/sec. based on long-term experience, σ can be assumed to be 245 cm/sec. (a) find a 95% confidence interval for the population mean wind speed at this site. (round your answers to the nearest whole number.) lower limit cm/sec upper limit cm/sec

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.

The ratio of the ages (in years) of three children is 2: 4: 5. the sum of their ages is 33. what is the age of each child?