Question 25 of 44beginner🔧 ApplyShort Answer4 marks
Find the sum of the following APs:
(i)
2, 7, 12, ..., to 10 terms.
Answer
245
(ii)
-37, -33, -29, ..., to 12 terms.
Answer
-180
(iii)
0.6, 1.7, 2.8, ..., to 100 terms.
Answer
5505
(iv)
1/15, 1/12, 1/10, ..., to 11 terms.
Answer
33/20
Explanation
This question requires applying the sum formula for Arithmetic Progressions. The context provides two equivalent formulas: S = n/2 [2a + (n-1)d] and S = n/2 (a + l). For each part, students need to identify the first term (a), common difference (d), and number of terms (n), then substitute into the formula. The common difference is found by subtracting the first term from the second term. Careful calculation with fractions and decimals is essential.