28. its the lowest one in the group
The answer would be the top right device.
C) 2/9 , because dividing both 8 and 36 by 4 will leave the numerator as 2 (8/4=2) and the denominator as 9 (36/4=9).
a) The sum of your ages is F + (F+B) = 2F+B.
b) In 3 years, the sum of your ages will be (F+3)+(F+B+3) = 2F+B+6.
c) The difference of your ages at any time is B.