Step: Find the one who made more runs per over
Given: Runs scored by A in 6 overs = 84 runs
Runs scored by B in 7 overs = 126 runs
⇒ Runs scored by A in one over = 846
= 14 runs
⇒ Runs scored by B in one over = 1267
= 18 runs
Therefore, in one over runs scored by B is more than A .
Hence, B made more runs per over.