Mathematics 2015 JAMB Past Questions - Question 6: Find the sum of the first 10 terms of the A.P 3+10+17+....

Correct Answer

A

Explanation

a=3,d=7,n=10Sn =n/2<2a+(n-1)d>S₁₀ =10/2<2*3+(10-1) > s₁₀= 5 <6 + 9 * 7> , s₁₀ = 5 X 69 = 345To find the sum of the first 10 terms of the arithmetic progression (A.P.) 3, 10, 17, ..., we can use the formula for the sum of the first n terms of an arithmetic progression:Sn = n/2 * (2a + (n-1)d)Where:Sn = sum of the first n termsn = number of termsa = first termd = common differenceIn this case:a = 3 (the first term)d = 10 - 3 = 7 (the common difference)n = 10 (the number of terms)Now, we can substitute these values into the formula:Sn = 10/2 * (2*3 + (10-1)*7)  = 5 * (6 + 63)  = 5 * 69  = 345Therefore, the sum of the first 10 terms of the given arithmetic progression is 345.