Answer
At $t=0, [B]=0M$.
At $t=10, [B]=0.014M$.
At $t=20, [B]=0.023M$.
At $t=30, [B]=0.029M$.
At $t=40, [B]=0.034M$.
Work Step by Step
From the reaction $A(aq) -> B(aq)$, it can be inferred that 1 mol of A lost means 1 mol of B is produced.
At t=0, there are no molecules of B, so $n_{B}=0 (mol)$
At t=10, there is 0.051 mol A left. Which means $0.065-0.051=0.014(mol)$ of A has reacted to form $0.014mol$ of B.
Likewise, at t=20, $0.065-0.042=0.023(mol)$ of A has reacted to form $0.023mol$ of B.
At t=30, $0.065-0.036=0.029(mol)$ of A has reacted to form $0.029mol$ of B.
At t=40, $0.065-0.031=0.034(mol)$ of A has reacted to form $0.034mol$ of B.
