a$)$ a $5$ year bond is priced par value when the interest rate in the economy is $4\%.$ what will happen to its price if the interest rate increases to $6\%?$ Would the effect have been different for a $30$ year bond? why? c$)$ what happens to the coupon rate of a $$1000$ face value bond that pays $$80$ annually in interest if market interest rates change from $9\%$ to $10\%?$