Washi Co

Hello Sir, For PYQ Sept 2018 Q1 Washi Co

I have a question about the exchange rate used to calculate the additional tax payable –
( ARD Pre-tax Profits)

Should we convert to JPY first(i) or calculate the tax payable at 15% and then convert to JPY?(ii)

(i) If convert first, then as its profit(cash inflows), should it divide at the higher rate?(0.8534)

(ii)if calculate the tax payable first, then as its cash outflows so use the lower rate as what examiner did.

or its usually used the lower rate(divide) as its payment?

Thank you.