Create the spreadsheet models shown in the following figure below Figure $1$ using the formula shown for appropriate cells in MS Excel.

$\backslash$table$[[,$A$,$B$,$C$,$D$,$E$,$F$,$G$,H,$I,J$,$K$],[1,$Simple Loan Calculation Model in Excel$],[2,,,,,,,,,,,],[3,$Loan Amount,$$150,000,,,,,,,,,],[4,$Interest Rate,$8\mathrm{.}00\%,,,,,,,,,],[5,$Numer of Years,$30,,,,,,,,,],[6,,,,,,,,,],[7,$Number of Months,$360,,=B5**12,,,,,,,],[8,$Interest Rate$/$Month$,0\mathrm{.}67\%,$larr,$=B\frac{4}{12},,,,,,,],[9,,,,,,,,,],[10,$Monthly Loan Payment,$($$$1,100\mathrm{.}65),$larr,$=PMT(B8,B7,B3,0),,,,,],[11,,,,,,,,,],[12,,,,,,,,,],[13,($NB: PMT funct,ion calcul,ates the payr,ent for a l$,$an be$,$n cor,tpay,and,stant,est rate$)],[14,,,,,,,,,,]]$

Fig. $1$

a$.$ What is the effect on Monthly Loan Payment of a change in the interest rate from $8\%$ to $10\%$ in the spreadsheet model shown in Figure $1?$

b$.$ For the original model in Figure $1($at $8\%$ interest$),$ what would be the Monthly Loan Payment if the Number of Years for payment is $15?$