Grandpa Zhang raised 28 chickens, and the ducks he raised accounted for 75% of the chickens. How many chickens and ducks does Grandpa Zhang raise in total?
张爷爷家养鸡28只，养的鸭是鸡的75%．张爷爷家养鸡和鸭共多少只？
<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">28 * (3/4)</gadget>
<output>21</output>

<gadget id="calculator">21 + 28</gadget>
<output>49</output>

<result>49</result>