MATHEMATICS

JAMB 2003 - Question 22

Mathematics 2003 JAMB Past Questions - Question 22: The sum of the first n terms of an arithmetic progression is 252.If the first term is -16 and the last term is 72, find the number of terms in the series .

The sum of the first n terms of an arithmetic progression is 252.If the first term is -16 and the last term is 72, find the number of terms in the series .
A:
B:
C:
D:
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Correct Answer

D

Explanation

To find the number of terms in the arithmetic progression, we can use the formula for the sum of an arithmetic series:Sn = (n/2)(a + L)where Sn is the sum of the first n terms, n is the number of terms, a is the first term, and L is the last term.Given that Sn = 252, a = -16, and L = 72, we can substitute these values into the formula:252 = (n/2)(-16 + 72)Simplifying the equation:252 = (n/2)(56)Dividing both sides by 56:252/56 = n/24.5 = n/2Multiplying both sides by 2:9 = nTherefore, the number of terms in the series is 9.