What is the answer for number 1 and how did you solve it ?

Use this data in the problem below. follow the steps carefully. round to the nearest tenth. lot 3: week 1: 345 week 2: 340 week 3: 400 week 4: 325 step 1. jim enters the data and calculates the average or mean. step 2. jim calculates the deviation from the mean by subtracting the mean from each value. step 3. jim squares each deviation to remove negative signs. step 4. jim sums the squares of each deviation and divides by the count for the variance. step 5. jim takes the square root of the variance to find the standard deviation.

How many $20 bills do you need to have to make $280

For what value of (y) is 3^3/3^y =1/9