Sheena has a pet frog and it is growing fast and eating more flies each day. When she first brought it home on Monday it ate 3 flies, Tuesday it ate 6, Wednesday it ate 9, and Friday it ate 15.
How many flies did her frog eat on Thursday?	Choose the correct answer:
A) 12
B) 14
C) 10
D) 11
E) 13
A) 12. The frog started eating 3 more flies each day.   3 +3= 
<gadget id="calculator">3 +3</gadget>
<output>6</output>
6   6+3= 
<gadget id="calculator">6+3</gadget>
<output>9</output>
9   9+3= 
<gadget id="calculator">9+3</gadget>
<output>12</output>
12   12+3= 
<gadget id="calculator">12+3</gadget>
<output>15</output>
15
<result>A</result>
Sheena has a pet frog and it is growing fast and eating more flies each day. When she first brought it home on Monday it ate 3 flies, Tuesday it ate 6, Wednesday it ate 9, and Friday it ate 15.
How many flies did her frog eat on Thursday?