Please Prove This Problem By Doing in LHS side. I try my best but i couldn't solve this. so please solve it.
​

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

What is the percentile for data value 6 in the following data set? 4 13 8 6 4 4 13 6 4 13 2 13 15 5 9 4 12 8 6 13 40 25 35 62

Olga bought a new skirt that cost $20. sales tax is 5%. how much did olga pay, including sales tax? 7.