A store has sold 90 notebooks, which is 20% of all the
notebooks they had. How many notebooks did the store
have at first?

A) 450
B) 23
C) 108
D) 500

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

Thompson and thompson is a steel bolts manufacturing company. their current steel bolts have a mean diameter of 127 millimeters, and a variance of 36. if a random sample of 35 steel bolts is selected, what is the probability that the sample mean would differ from the population mean by greater than 0.5 millimeters? round your answer to four decimal places.

Write the equations in logarithmic form 10^3=1,000