Lakshmi has $100 in her piggy bank. How much will she have in her bank 15 weeks from now if she puts $1 in the bank next week, $2 two weeks from now, $3 three weeks from now, and continues to increase the amount that she puts in by $1 each week?	Choose the most appropriate option
A) 210 B) 220 C) 230 D) 240 E) 250
The dollar deposits are in an A.P.   1,2,3,4...15with common difference 1   Sum of the terms is n(n+1) / 2   i.e 15* (15+1) /2   = 15* 16/2= 
<gadget id="calculator">15* 16/2</gadget>
<output>120</output>
120   Total deposit therefore with Chiu-Lihas is 100 + 120= 
<gadget id="calculator">100 + 120</gadget>
<output>220</output>
220$
<result>B</result>
Lakshmi has $100 in her piggy bank. How much will she have in her bank 15 weeks from now if she puts $1 in the bank next week, $2 two weeks from now, $3 three weeks from now, and continues to increase the amount that she puts in by $1 each week?