If the average (arithmetic mean) of a, b, and c is 40, what is the average (arithmetic mean) of (3a + 10), (3b +10), and (3c+10)?
সমাধান
সঠিক উত্তর: Option C
(a + b + c) / 3 = 40
or, a + b + c = 120
or, 3 * (a + b + c) = 120 * 3
or, 3a + 3b + 3c = 360
or, 3a + 3b + 3c + 30 = 360 + 30
or, (3a + 10) + (3b + 10) + (3c + 10) = 390
or, [(3a + 10) + (3b + 10) + (3c + 10)] / 3 = 390/3
= 130
