Kai and Paola put some money into their money boxes every week. The amounts of money (y), in dollars, in their money boxes after a certain amount of time (x), in weeks, are shown by the equations below:

Kai: Y = 30x + 20
Paola: Y = 20x + 90

After how many weeks will Kai and Paola have the same amount of money in their money boxes, and what will that amount be?

1 answer

To find the number of weeks when Kai and Paola will have the same amount of money in their money boxes, we need to set their equations equal to each other and solve for x:

30x + 20 = 20x + 90
30x - 20x = 90 - 20
10x = 70
x = 7

Therefore, after 7 weeks, Kai and Paola will have the same amount of money in their money boxes.

To find the amount of money they will have after 7 weeks, we can substitute x = 7 into either equation:

For Kai:
Y = 30(7) + 20
Y = 210 + 20
Y = 230

For Paola:
Y = 20(7) + 90
Y = 140 + 90
Y = 230

Therefore, after 7 weeks, both Kai and Paola will have $230 in their money boxes.