Cait purchases a $20 item at a store. she uses a coupon to receive a 15% discount and she pays 6% on the item. she calculates the total cost, in dollars, of the item using the expression shown.

cait's expression: (1.15)(1.06)(20)

part a: describe the error in the expression cait used for her calculation.

part b: show or explain how you would calculate the total cost of cait's purchase.

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