A family of 2 adults and 4 children visited Sentosa during the June holidays.An adult ticket cost $18.90 and a child ticket $12.80 during the promotional period.if the family enjoyed the promotional price,what was the total cost of the tickets for the family ?and what would be the change if a $100-note was used to purchase the tickets ?

100 - (2*18.90 + 4*12.80)

To calculate the total cost of the tickets for the family, we need to multiply the number of adults by the cost of an adult ticket and the number of children by the cost of a child ticket, then sum the results.

Number of adults = 2
Number of children = 4

Cost of an adult ticket = $18.90
Cost of a child ticket = $12.80

Total cost of adult tickets = Number of adults * Cost of an adult ticket
= 2 * $18.90
= $37.80

Total cost of child tickets = Number of children * Cost of a child ticket
= 4 * $12.80
= $51.20

Total cost of tickets for the family = Total cost of adult tickets + Total cost of child tickets
= $37.80 + $51.20
= $89.00

So, the total cost of the tickets for the family would be $89.00.

To calculate the change if a $100 note was used to purchase the tickets, we need to subtract the total cost of the tickets from the amount paid.

Amount paid = $100.00
Total cost of the tickets = $89.00

Change = Amount paid - Total cost of the tickets
= $100.00 - $89.00
= $11.00

Therefore, the change would be $11.00 if a $100 note was used to purchase the tickets.