Answer:
Karen: 15; Dale: 9; Tom: 60
Explanation:
"Karen and Dale and Tom sent a total of 84 messages during the weekend."
k + d + t = 84
"Dale sent six fewer messages than Karen"
d = k - 6
"Tom sent four times as many as Karen."
t = 4k
Substitute k - 6 for d and 4k for t in the first equation.
k + d + t = 84
k + k - 6 + 4k = 84
6k - 6 = 84
6k = 90
k = 15
d = k - 6 = 16 - 6 = 9
t = 4k = 4(15) = 60
Answer: Karen: 15; Dale: 9; Tom: 60