Q.206- The average of five numbers is 7. When three new numbers are included, the average of the eight numbers becomes 8.5. The average of the three new numbers is :
Q.207- The average age of a family with 5 members is 28. If one of the 5 members of age 20 is excluded the average age of the family becomes.
Q.208- The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is :
Q.209- The average pocket money of 3 friend A, B, C is Rs. 80 in a particular month. If B spends double and C spends triple of what A spends during that month and if the average of their unspent pocket money is Rs. 60, then A spends (in Rs.)-
Q.210- The average age of group of 20 girls is 15 years and that of another group of 25 boys it is 24 years. The average age of the two groups mixed together is :