CBSE - Aptitude Mathematics

The average age of a class of 20 children is 11 years 3 months and the standard deviation is 5 months. A new student whose age is 13 years is added to the class. The average age of the new class is 1.10 years 2.11 years 3.10 years 4 months 4.11 years 4 months

What % of 40 is 8.484? 1.21.21 2.30% 3.21% 4.none of these

The unit's digit in the product 7 35 x 3 71 X 11 55 is (1) 1 (2) 3 (3) 7 (4) 9

A worker is paid r dollars for each hour he works up to 8 hours a day. For any time worked over 8 hours he is paid at the rate of (1.5)r dollars an hour. The total amount of dollars the worker will earn if he works 11 hours in a day is 1. (4.5)r 2. (5.5)r 3. (9.25)r 4. (12.5)r