Question 1030274
Hi there,
Steve is 19 years older than his sister Ann
S = A + 19.....(1)
In 16 years, he will be twice as old as Ann.  
S + 16 = 2(A + 16)......(2)
Replace S in Eq(2) with (A + 19) from
Eq(1)
A + 19 + 16 = 2(A + 16)
A + 35 = 2A + 32
Collect like terms:
2A - A = 35 - 32
A = 3
Ann is 3 years old.
Steve is 22 years old
.................
In 16 years:
Ann will be 19 years old
Steve will be 38 years old.
Hope this helps :-)