In boring a well 50 m deep, the cost is
Rs.4/– for the first meter. The cost of each successive meter
increases by Rs.2/–. What is the cost of boring the entire well?  Choices:
A) 1650  B) 2650  C) 3650  D) 4650  E) 2850
For successive meters the cost of boring will be 4, 6, 8, 10, ......., which forms an arithmetic series with terms n=50, first term a=4 &amp; difference d=2   So Sum=(n/2)[2a+(n-1)d]= Total cost of boring   =(50/2)[2*4+(50-1)*2]=25(8+98)   = 2650   ANSWER:2650
<result>B</result>
In boring a well 50 m deep, the cost is
Rs.4/– for the first meter. The cost of each successive meter
increases by Rs.2/–. What is the cost of boring the entire well?