Buy Van

$$30,532$

Lease Van

$$13,953$

Per Year

Buy$/$Lease Term

$3$

Years

Depreciation Term

$10$

Years

Tax Rate

$21\mathrm{.}0\%$

Interest Rate

$7\mathrm{.}6\%$

After$-$Tax Interest Rate

$6\mathrm{.}0\%$

Buy

Year

$1$

$2$

$3$

Payment

$$11,762$

$$11,762$

$$11,762$

Depreciation

$$3,053$

$$3,053$

$$3,053$

Tax Deduction

$$641$

$$641$

$$641$

Net Payment

$$11,121$

$$11,121$

$$11,121$

Lease

Year

$1$

$2$

$3$

Payment

$$13,953$

$$13,953$

$$13,953$

Tax Deduction

$$2,930$

$$2,930$

$$2,930$

Net Payment

$$11,023$

$$11,023$

$$11,023$

The requirement formuala : Buy price $-($Lease PaYMENT $-$ BuyTaxDeduction x $((1-($xAfterTaxInterestRate$^$x$))/$ AfterTaxInterestRate$)$

Although the question is what is the NPV leasing vs purchasing? Then you don't have to calculate the NPV of both, you have to use the above formula. $($x represents any other number in the question that I don't know$)$