Using properties of determinants, evaluate `|18 40 89 40 89 198 89 198 440|dot`

The value of Delta by using the properties of determinant where Delta = |{:(265,240,219),(240,225,198),(219,198,181):}| is

By using an appropriate identity , find the following : 89 xx 111

Find the sum of given terms:- (a)81 + 82 + 83 ............ + 89 + 90

Find the mean of the following distribution: 10 30 50 70 89 7 8 10 15 10