Question 1034953
Call the ages of Emily and Sean NOW, e and s.  Then we write
e + 1 = 2s   or e = 2s - 1
e - 4 = 3(s - 4)
Substitute in and get
2s-1 - 4 = 3(s - 4)
2s - 5 = 3s - 12
ow add 12 and subtract 2s...we get
s = 7 which means
e = 2(7) - 1 = 13