U.S.Dollar/British Pound. Assuming the same initial values for thedollar/pound cross rate in this table

how much more would a call option on pounds be if the maturity increases from 90 to 180 days? What percentage increase is this for the length ofmaturity?

I already have the correct answers but I need to know how to get those answers

Pricing Currency Options on the Euro

A U.S.-based firm wishing to buy

A British firm wishing to buy

or sell euros (the foreign currency)

or sell dollars (the foreign currency)

Variable

Value

Variable

Value

Spot rate (domestic/foreign)

S0

$

1.8674

S0

0.5355

Forward rate (domestic/foreign)

F0

$

1.8533

F0

0.5396

Strike rate (domestic/foreign)

X

$

1.8000

X

0.5556

Domestic interest rate (% p.a.)

rd

1.453

%

rd

4.525

%

Foreign interest rate (% p.a.)

rf

4.525

%

rf

1.453

%

Time (years, 365 days)

T

0.247

T

0.247

Days equivalent

90.00

90.00

Volatility (% p.a.)

s

9.400

%

s

9.400

%

d1

0.64800

d1

-0.60212

d2

0.60128

d2

-0.64884

N(d1)

0.74151

N(d1)

0.27355

N(d2)

0.72617

N(d2)

0.25822

Call option premium (per unit fc)

c

$

0.0669

c

0.0041

Put option premium (per unit fc)

p

$

0.0138

p

0.0199

(European pricing)

Call option premium (%)

c

3.58

%

c

0.77

%

Put option premium (%)

p

0.74

%

p

3.72

%

If the maturity increases from 90 to 180 days, a call option on pounds would be $ 0.069620

Therefore, the180-day call option would be $0.002730/ more than the 90-day call option.

The percentage increase for the length of maturity is 4.1899%

Can you help me getting these correct answers by showing calculation? If possible showing in excel please.