Zachary's gross salary is £2,080 per month. In April he paid income tax of £270, trade union contributions, plus 4.5% of his gross salary in pension contributions. His total deduction from gross salary is £390.
Calculate
(i) how much Zachary paid in pension contributions in April
(ii) how much Zachary paid in trade union contributions in April
(iii) the ratio of net pay to gross pay. Express your ratio in its simplest terms