Answer:
a). 
b). V = 15 units
Step-by-step explanation:
Focal length F of a lens made by combining two lenses of different focal lengths U and V will be,

A). By solving the given formula,



B). If F = 6 and U = 10 then we have to find the value of V.
By substituting the given values in the formula,


V = 15 units
Therefore, focal length (V) of the lens = 15 units
162 = never use a credit card
1223 = use credit card sometimes
2831 = use a credit card frequently
Probability that a randomly selected person uses a credit card frequently:
1223 / 162 + 1223 + 2831
1223 / 4216
As a percentage, this is about a 29 percent chance. I guess you could say it's unlikely, because the probability is only 29 percent.
The fact that the survey was taken on the internet means it's not really a reliable survey, because only those who have access to the internet would be able to take the survey, which rules out a good group of people.
Right now?????????????????????
It means 3 is multiplied by x