উত্তর সিলেক্ট করলে সঠিক ও ভুল দেখাবে।
ব্যাখ্যা ও সঠিক সমাধান
উত্তর:
27
we must take such a value of n for which the average must be in between 18 to 21, inclusive. It means 21 can be the average . We are looking fro greatest value of n. So, we must take 21 as average of this 3 numbers.
16 + 20 + n = 3×21
= > 36 + n = 63
∴n = 27.