model 6 operations of consecutive numbers (odd, even, square, etc.) Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (b)

x + x + 1 + x + 2 = 27

3x + 3 = 27

3x = 24

x = 8

Three consecutive no's whose sum is 27 are 8, 9,10.

Hence, next 3 consecutive no's having 36 as sum are 11, 12 and 13

Answer: (d)

According to the question,

First number = a = 103; Last number = l = 998

If the number of such numbers be n, then,

998 = 103 + (n – 1) × 5

(n – 1) × 5= 998 – 103 = 895

n – 1 = $895/5$ = 179

n = 180

S = $n/2(a+l)$

=$180/2$(103 +998)

= 90 × 1101 = 99090

Answer: (d)

S = 1 + 3 + 5 + ..... to 50 terms

Here, a = 1; d = 3 – 1 = 2; n = 50

S = $n/2[2a + (n - 1)d]$

= $50/2[2×1+ (50 - 1) ×2]$

= 25 (2 + 98) = 25 × 100 = 2500