Find the missing (?) number: 1, 6, 15, ?, 45, 66, 91
সমাধান
সঠিক উত্তর: Option A
Pattern in the series is, +5, +9, .., .., +21, +25 So 4 is getting increased at every term addition. Missing term in the series will be 15+(9+4) = 15+13 = 28
