Answer:
The total amount of money Alison and Justins father donated be $108 .
Explanation:
Distributive property.
Let a, b and c be any real numbers.
Thus
a.( b + c ) = a.b + a.c
This is distributive property.
As given
Alison and Justins father donated $3 every lap they swam in a swim-a-thon.
Alison swam 21 laps and justin swam 15 laps.
Total amount of money Alison and Justins father donated = Cost of each lap (Number of laps of Alison father + Number of laps of Justins father )
As
Cost of each lap = $3
Number of laps of Alison father = 21 laps
Number of laps of Justins father = 15 laps
Putting in the above
Total amount of money Alison and Justins father donated = 3(21 + 15)
= 3 × 21 + 3 × 15
= 63 + 45
= $ 108
Therefore the total amount of money Alison and Justins father donated be $108 .