I need help in solving exercise $7.$

Practical Application: Consider the following corporate and muni bond info from Thursday $2/11/2021$

$($Settlement is T$+2$ i$.$e$.2/15/2021).$ All the bonds are semiannual.

EXERCISE #$4$: If Western Union $2040$ gets downgraded to BB$+$ and the yield changes by

$1\%,$ then for Western Union $2040$ :

New $ytm=$

$\%,$ New approx. Price :

$[$Assume exactly $\frac{191}{2}$ years to maturity.$]$

EXERCISE #$5$: Compute the taxable$-$equivalent yield to maturity on the UtahStBldg $2038$

bond for a Utah resident paying a $25\%$ federal and a $7\%$ state income tax $($add$).$

Tax$-$eq yield $=$

EXERCISE #$6$: Compute the approx yield to call on the Salt Lake Arpt $2047.$ Assume $61/2$

years to call.

$YTC=,1\%$

EXERCISE #$7$: Compute the Mod Duration of the EastmanChem $2044$ bond by "blipping".

$[231/2$ years to maturity$]$ That is$,$ compute three prices: at the current ytm$,$ and by changing

the ytm by $0\mathrm{.}05\%$ up and down. Then follow the ModD definition. Rescale correctly.

ModD$=-\%\frac{}{}y=-\frac{P_{+5}-P_{-5}}{P}\frac{?}{(y_{+5}-y_{-5})}$