a rower can row 5 km / h in still water. when the river is running at 2 km / h, it takes the rower 1 hour to row to big rock and back. how many kilometers is it to big rock?	Choose the correct choice from the following answers:  A) 1.5  B) 1.8  C) 2.1  D) 2.4  E) 2.7
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 3</gadget>
<output>10</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 7</gadget>
<output>21/10 = around 2.1</output>

<result>C</result>
a rower can row 5 km / h in still water. when the river is running at 2 km / h, it takes the rower 1 hour to row to big rock and back. how many kilometers is it to big rock?
multiply(divide(subtract(5, 2), add(add(5, 2), subtract(5, 2))), add(5, 2))
"let x be the distance to big rock . time = x / 3 + x / 7 = 1 x = 21 / 10 = 2.1 km the answer is c ."