Brittany, Alex, and Jamy all share 600 marbles divided between them in the ratio 3:5:7. If Brittany gives Alex half of her marbles, what's the total number of marbles that Alex has?
The total ratio representing the number of marbles is 3+5 +7 = 
<gadget id="calculator">3+5+7</gadget>
<output>15</output>
15.
From the ratio, the fraction representing the number of marbles that Brittany has is 3/15, which is equal to 3/15*600 = 
<gadget id="calculator">3/15*600</gadget>
<output>120</output>
120 marbles.
Alex has 5/15*600 = 
<gadget id="calculator">5/15*600</gadget>
<output>200</output>
200 marbles.
If Brittany gives half of her marbles to Alex, Alex receives 1/2*120 = 60 marbles.
After receiving 60 marbles from Brittany, Alex has 200+60 = 
<gadget id="calculator">200+60</gadget>
<output>260</output>
260 marbles.

<result>260</result>