Answer:
5y + 3 is the sum of the three ages
Step-by-step explanation:
Let y=Mark, d=Daniel j=Jack, and s=The sum
Mark is y years old. In five years jack will be twice as old as Mark
j + 5 = 2(y+5)
j + 5 = 2y + 10
j = 2y + 10 - 5
j = 2y + 5
Daniel will be two years younger than jack is now
d + 5 = j - 2
d = j - 2 - 5
d = j - 7
Replace j with (2y+5)
d = (2y+5) - 7
d = 2y - 2
Expression in terms of y for the sum of the 3 ages now
s = y + j + d
replace j and d with expressions we came up with above
s = y + (2y+5) + (2y-2)
s = y + 4y + 3
s = 5y + 3 is the sum of the three ages
