Annuities X and Y provide the following payments:

End of the Year// Annuity X // Annuity Y

1-10 // 1 // K

11-20 // 1 // 0

21-30 // 1// K

Annuities X an dY have equal present value (at time 0) at an annual effective interest rate i such that v^10=0.5. Determine K.

BE THOROUGH PLEASE so I can understand fully.