Four numbers are in proportion. The sum of the squares of the four numbers is 50 and the sum of the means is 5. The ratio of the first two terms is 1:3. What is the averages of the four numbers?
Options:
a)2 b)3 c)5 d)6
My approach: $a+b+c+d=(average*observations)$(Taken from the options)
The sum of means and ratio of the first two terms can be obtained from the options. I intend to prove it that way but I do not know what to do next. Also how many equations do I exactly need if I intend to solve this set of equations is something that always bother me. I think I need to have a thorough understanding of number of variable and number of equations.