$10$

$(1\mathrm{.}2)$

Calculate the "Room Total" for the first transaction.

Use an IF function to calculate a $10\%$ discount for any stay greater than or equal to $7$ nights.

Copy and paste the function down the column to calculate the room total for the other transactions.

$10$

$(1\mathrm{.}3)$

Calculate the "Add$-$On Total" for the first transaction. Rooms with $3$ or more guests are required to pay the add$-$on fee.

Use an IF function with a nested