How many men paid for a total amount of $262,143.75 if the first person to arrive only paid 25 cents? Date of Exam November 1994 Subject Mathematics, Surveying and Transportation Engineering Problem In a fund raising show, a group of philanthropists agreed that the first one to arrive would pay 25¢ to enter, and each later would pay twice as much as the preceding person. The total amount collected from all of them was \$262,143.75. How many of them paid? A. 110 C. 50 B. 20 D. 80 Answer Key Click here to show or hide the answer key [ B ] Solution Click here to expand or collapse this section 0.25, 0.50, 1, 2, ... ← is a GP with r = 2 $S = \dfrac{a_1(r^n - 1)}{r - 1}$ $262,143.75 = \dfrac{0.25(2^n - 1)}{2 - 1}$ $2^n = 1,048,576$ $n = 20$ ← answer Category Algebra Progression Geometric Progression Sum of Geometric Progression Number of Terms in an Geometric Progression Log in or register to post comments