9708/12 Economics Oct Nov 2019 Online Test | Cambridge AS and A Level MCQ

Country X conducts 60% of its trade with country Y and 40% of its trade with country Z. The initial value of the trade weighted exchange rate index of country X is 100.
What will be its new trade weighted exchange rate index value if its currency rises in value by 20% against the currency of Y and falls by 10% against the currency of Z?