Puzzle of the week #350

Level: 
2-Knight
Chess Diagram: 

[Event "Puzzle #350"][Date "2018.06.02"][Result "1-0"][SetUp "1"][FEN "6RK/8/3k4/2p5/8/8/8/8 w - - 0 1"]

White has a Rook for a pawn material advantage in this endgame. It remembers that in order to win it needs to win the pawn, but does not remember how. Your tasks:
a) Find the winning line
b) Explain how you came up with it

Total available points for this puzzle is 30. The answers will be published next time together with puzzle #351.

Puzzle #349 solution:
Questions by Valer Eugen Demian, 2018. This week's best answers are by the top scorers:
Answer (a)

[Event "Puzzle #349"][Date "2018.05.27"][Result "1/2-1/2"][SetUp "1"][FEN "3Q4/1K6/8/8/8/8/pk6/8 w - - 0 1"]{The position is a draw because the black King can hide in the corner in front of the a2-pawn, threatening stalemate. The white King cannot come and help} 1.Qd2+ Kb1 2.Qb4+ Ka1 3.Qa3 Kb1 4.Qb3+ Ka1 {Draw}

Answer (b)
[Event "Puzzle #349"][Date "2018.05.27"][Result "1-0"][SetUp "1"][FEN "3Q4/8/8/1K6/8/8/pk6/8 w - - 0 1"]{The position is a win. White will check from the side and then bring its King close. When black promotes, its Queen cannot stop the checkmate} 1.Kb4 a1=Q 2.Qd2+ Kb1 3.Kb3 {White wins}

Answer (c)
[Event "Puzzle #349"][Date "2018.05.27"][Result "1/2-1/2"][SetUp "1"][FEN "3Q4/1K6/8/8/8/8/1kp5/8 w - - 0 1"]{The position is a draw because the Queen cannot capture the c2-pawn. The black King goes in the corner and in case of capture, we have stalemate} 1.Qd2 Kb1 2.Qb4+ Ka1 3.Qc3+ Kb1 4.Qb3+ Ka1 {Draw}

Answer (d)
[Event "Puzzle #349"][Date "2018.05.27"][Result "1/2-1/2"][SetUp "1"][FEN "3Q4/8/8/1K6/8/8/1kp5/8 w - - 0 1"]{This was a trick question; the position is a draw like for question "c". It does not matter the white King is 2 rows closer} 1.Qd2 Kb1 2.Qb4+ Ka1 3.Qc3+ Kb1 4.Qb3+ Ka1 {Draw}

Correct solutions:
Coby, Mengbai, Matthew, Eric - 60 points
Aiden - 55 points
Jacey - 41 points
Joey - 40 points
Blake, Lyvia - 36 points
Walter - 32 points
Zhengyu, Itamar - 26 points
Lucas - 22 points
Brian, Glyn - 18 points
Chris - 5 points

Blake - 3 points for puzzle #348

Standings:
Matthew - 156 points
Aiden, Coby, Eric - 141 points
Joey - 128 points
Lyvia - 125 points
Mengbai - 116 points
Walter - 106 points
Zhengyu - 100 points
Blake - 85 points
Jacey - 72 points
Glyn - 69 points
Brian - 62 points
Lucas - 59 points
Itamar - 34 points
Chris - 15 points
Steven - 14 points

Comment: 

Rook versus pawn