There are 20 children at a library. Six of the children have an average age of 5 years. The remaining children have an average age of 8 years. What is the average age of the children at the library?

7.1

Step-by-step explanation:

6 children with an average age of 5 = 6*5 = 30 so the sum of their ages is 30

20 - 6 = 14

14 children have an average age of 8  14*8 =112 so the sum of their ages is 112

Add the two sums

30+112 = 142

Divide by the total number of children

142/20 =7.1

The average age of all the 20 children is 7.1

7.1

Step-by-step explanation

(30+(16*8))/ 20

if gloria has "carry over" minutes, (that is, any minutes paid for but not used in a month can be applied to her payment for minutes in the next month,) her total usage for the three months is: total minutes = 320 + 243 + 489 = 1052 minutes number of 200 minute blocks = 1052/200 = 5 r52 (that is 5 with a remainder of 52) rounding up the number of 200 minute blocks gives her usage for the three months as 6 blocks. the cost for six blocks is 6 x $25 = $150 she also has 200 - 52 or 148 carry over minutes if gloria pays each month and unused minutes are lost, applying the rounding up procedure to each month gives: first month usage of 320 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 second month usage of 243 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 third month usage of 489 minutes rounds up to 3 blocks of 200 minutes for a payment of 3 x $25 = $75 total payments for the three months are $50 + $50 + $75 = $175 get the plan with carry over minutes!