If bc:ac:ab=1:3:5, then find `(a)/(bc):(b)/(ca)`.

If a:b=4:5 and b:c=2:3, then a:c=

If bc + ab + ca = abc, then the value of (b+c)/(bc(1-a))+(a+c)/(ac(1-b))+(a+b)/(ab(1-c)) is

If a,b,c are in A.P., then (bc)/(ca+ab),(ca)/(bc+ab),(ab)/(bc+ca)

If a:b=3:1 and b:c=5:1 , then find the value of a^2/(7bc)

If a,b,c are in A.P. prove that: (i) (ab)^(-1),(ca)^(-1) and (bc)^(-1) are also in A.P. (ii) (ab+ac)/(bc),(bc+ca)/(ca),(ca+cb)/(ab) are also in A.P.

If a, b, c are in A.P., prove that : (ab+ac)/(bc), (bc+ba)/ (ca), (ca+cb)/(ab) are also in A.P.