Both Bond X and Bond Y have $7,5\%$ coupon rate, make semiannual payments, and are priced at par value. Bond X has $15$ years to maturity while Bond Y has $20$ years to maturity. If interest rates suddenly rise by $2$ percents, what is the percentage change in the price of those bonds? On contrary, if interest rates fall by $2$ percents instead, what would happen to both bonds$$ prices?