a) Given :
51 pounds of seed can be planted in = 9 acre field.
Per pound of seed =

We can convert 9/51 in simplest fraction by dividing top and bottom by 3.
We get

Therefore, 3/17 of an acrs can be planted per pound of seed.
b) $10 amount = 16 pounds of sugar.
$1 amount = 16/10 = 1.6 pounds of sugar.
Therefore, 1.6 pounds of sugar she got per dollar.